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Tel: (03) 9546 2188
Fax: (03) 9562 3717
Unit 1, Sandown Square,
56 Smith Road,
SPRINGVALE VIC 3171
Tel: (03) 9546 2188
Fax: (03) 9562 3717
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June 1999
SEDA and SEAV Street Lighting Efficiency
file: 244 © Genesis Automation and Lightlab International June-99
File: 244
Contents
EXECUTIVE SUMMARY ……………………………………………………………………………………………………………… 1
Aim…………………………………………………………………………………………………………………………………………………………. 1
Findings………………………………………………………………………………………………………………………………………………….. 1
Strategy…………………………………………………………………………………………………………………………………………………… 1
INTRODUCTION………………………………………………………………………………………………………………………….. 2
Aim…………………………………………………………………………………………………………………………………………………………. 2
Report Organisation ………………………………………………………………………………………………………………………………… 2
Project Timing…………………………………………………………………………………………………………………………………………. 2
STREET LIGHTING IS IMPORTANT……………………………………………………………………………………………………. 3
Function………………………………………………………………………………………………………………………………………………….. 3
Safety ……………………………………………………………………………………………………………………………………………………… 3
Cost………………………………………………………………………………………………………………………………………………………… 3
Environment ……………………………………………………………………………………………………………………………………………. 3
OVERVIEW OF CURRENT STREET LIGHTING INFRASTRUCTURE…………………………………….. 4
THE STREET LIGHTING TASK …………………………………………………………………………………………………………. 4
What Should be Illuminated? ……………………………………………………………………………………………………………………. 4
How are the Street Lighting Areas Classified? ……………………………………………………………………………………………. 4
How Should these be Illuminated?…………………………………………………………………………………………………………….. 4
WHICH LIGHTING EQUIPMENT SHOULD BE USED?……………………………………………………………………………. 5
Overview…………………………………………………………………………………………………………………………………………………. 5
Is Lighting Colour Important? ………………………………………………………………………………………………………………….. 5
Other Equipment Selection Criteria…………………………………………………………………………………………………………… 7
HOW DOES THE PRESENT STREET LIGHTING INFRASTRUCTURE RATE?………………………………………………. 8
Light Colour ……………………………………………………………………………………………………………………………………………. 8
Light Distribution…………………………………………………………………………………………………………………………………….. 8
Efficiency ………………………………………………………………………………………………………………………………………………… 9
Overall Street Lighting Assessment………………………………………………………………………………………………………….. 11
OVERVIEW OF BEST PRACTICE STREET LIGHTING ………………………………………………………….. 12
AUSTRALIA AND NEW ZEALAND………………………………………………………………………………………………….. 12
New Australian New Zealand Standards :…………………………………………………………………………………………………. 12
Lighting for Main Traffic Routes : ……………………………………………………………………………………………………………. 12
INTERNATIONAL…………………………………………………………………………………………………………………………. 13
North America……………………………………………………………………………………………………………………………………….. 13
Europe ………………………………………………………………………………………………………………………………………………….. 14
STREET LIGHTING RECOMMENDATIONS ……………………………………………………………………………. 15
EQUIPMENT ……………………………………………………………………………………………………………………………….. 15
Available Light Sources………………………………………………………………………………………………………………………….. 15
Comparing Light Sources……………………………………………………………………………………………………………………….. 15
Lamps for the Lighting of Residential Streets…………………………………………………………………………………………….. 16
Lamps for the Lighting of Main Roads: …………………………………………………………………………………………………….. 17
Lanterns for Lighting Minor Roads ………………………………………………………………………………………………………….. 17
Lanterns for Lighting Main Roads ……………………………………………………………………………………………………………. 18
Ballasts …………………………………………………………………………………………………………………………………………………. 18
Lighting Control…………………………………………………………………………………………………………………………………….. 19
System Costs and Benefits ………………………………………………………………………………………………………………………. 20
IMPLEMENTATION………………………………………………………………………………………………………………………. 21
Field Trials……………………………………………………………………………………………………………………………………………. 21
Industry Facilitation ………………………………………………………………………………………………………………………………. 21
Representation on Standards Committee…………………………………………………………………………………………………… 21
FURTHER INVESTIGATION……………………………………………………………………………………………………………. 22
The Installation of Lighting Systems :……………………………………………………………………………………………………….. 22
Hardware Choice…………………………………………………………………………………………………………………………………… 22
Maintenance :………………………………………………………………………………………………………………………………………… 23
REFERENCES………………………………………………………………………………………………………………………………. 23
APPENDIX 1: NSW FLUORESCENT LANTERNS………………………………………………………………….. 24
APPENDIX 2: MAGAZINE ARTICLE, NEW STREET LIGHTING STANDARD ………………….. 25
APPENDIX 3 LAMPS COMPARISON……………………………………………………………………………………… 29
APPENDIX 4: COMPARISON OF TWO MINOR ROAD LANTERNS……………………………………. 31
APPENDIX 5 SEMI-CYLINDRICAL ILLUMINANCE:…………………………………………………………… 32
A Personal Note from Kevin Poulton……………………………………………………………………………………………………….. 32
APPENDIX 6: GLOSSARY ………………………………………………………………………………………………………. 34
APPENDIX 7: ABOUT THE AUTHORS ………………………………………………………………………………….. 35

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Executive Summary
Aim
This document aims to:
• identify opportunities to reduce the energy consumption of street lighting, while
improving the quality of illumination, and
• describe actions and a strategy which will result in realising the potential savings.
Findings
The key findings of this report are:
• present street lighting systems are inefficient, in that:
• the quality of illumination of both minor and major roads is much lower than can be
achieved, and
• the energy efficiency is low.
• there is a basic mismatch between the light colour produced by many street lights and the
light colour which the human eye can use under typical street lighting vision conditions.
• the quality of street lighting can be significantly improved, and the energy consumption at
least halved by a combination of:
• more efficient lamps (eg. metal halide and compact / tubular fluorescent).
• more efficient lanterns (reflector design, less light loss in diffuser, more accurate light
distribution without a refractor bowl),
• more efficient ballasts, especially electronic ballasts.
• more accurate control of lighting times (electronic photo-switch rather than the
existing cadmium sulphide cells, to reduce burning time by at least an hour per day (9%)).
• the capital cost premium of energy efficient street lighting is small and is justified by the
very high return1 on the small premium, and:
• the cost of energy efficient street lighting equipment is very likely to fall as the
production volumes increase.
• the cost of upgrading street lighting efficiency is comparatively low now because the
majority of NSW and Victorian minor roads street lights are due for replacement now or
within five years.
• the higher cost of more accurate, electronic photo-switches is justified by their longer
life, with energy savings due to shorter lighting hours being a free benefit.
• mercury vapour is reputed to have low maintenance costs, but this reputation is largely a
result of the practice of not replacing lamps even when light output has fallen excessively
because of lamp fading.
Strategy
This report recommends:
• field trials of a range of street lights,
• facilitating manufacture of energy efficient street lighting equipment, and
• SEDA / SEAV representation on Standards Australia committees relevant to street
lighting.
1 74% p.a. for the street lighting solution described in “System Costs and Benefits” on page 20.
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Introduction
Aim
Terms of Reference
The brief for this project stated that the aims were:
• assessment of the current technology used in providing street l ig ht in g i n Vic to ri a a nd
NSW,
• assessment of interstate and international best practice, and
• recommending methods of reducing energy consumption and maintenance costs.
This report does not discuss the issue of competitive supply of street lighting services, as this
is well covered by Reference 4 (please see page 23).
Project Team Aim
The project team hope that this document will promote discussion and investigation of the
street lighting task and strategies.
Report Organisation
This report is organised into the following sections:
• Street Lighting is Important One page overview of its importance and impact
• Current Street Lighting Infrastructure The street lighting task and how it is now tackled
• Best Practice Street Lighting Providing the greatest? benefits at the lowest cost
Other supporting documentation is in the Appendices.
Project Timing
This is an opportune time to be reviewing street lighting:
• In Victoria, about 200,000 mercury vapour (80 Watt) lanterns were installed starting in
1989. This project saw the replacement of twin 20 Watt fluorescent lamp lanterns. The
new street lights have an estimated service life of 15 years, and so planning of the next
generation of replacement fittings must start now. This will allow adequate time for
design, hardware selection and / or development, and field trials.
• NSW has about 400,000 fluorescent street lighting lanterns2, which are programmed for
replacement now. If NSW were to adopt the same solution to fluorescent lantern
replacement which Victoria took:
_ the capital would be about $M70
_ energy consumption for these lanterns would double, and
_ the recurring greenhouse gas emissions will be 146 kilo-tonnes3 every year.
2 Details of the NSW fluorescent street lighting lantern numbers and costs are in Appendix 1 on page 24.
3 based on 158.9 GWh/year (see Appendix 1) and a greenhouse intensity of 0.92 kg/kWh.
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Clearly, the benefits of the NSW replacement of fluorescent street lighting need to be
maximised while minimising the costs to the community and the environment.
Street Lighting is Important
Function
Good street lighting contributes to the quality of life, by improving personal safety and
perceived safety, and improving the appearance of the local environment. As a corollary,
poorly designed lighting systems can degrade the quality of life, for example, by making
vision more difficult, or through intrusive unwanted light.
Safety
There is a considerable body of knowledge which indicates that the provision of lighting on
roadways has a significant effect on the lowering of accident rates at night.
Therefore the provision of acceptable lighting systems on all roadways is not just a matter of
amenity, but also quite literally a matter of life and death.
For most people, probably the worst fear when venturing out at night is that they may be
accosted by a stranger. If the lighting, and particularly the vertical lighting, is insufficient it
will be very difficult for anyone to make a confident judgement as to whether or not someone
approaching is a friend or foe. We are of the opinion that this widely felt fear is one of the
most significant reasons why people do not wish to go out into public spaces during the hours
of darkness.
Cost
However the provision of street lighting systems comes at a significant cost to the
community.
Street lighting costs the Australian community about $M156 per year in energy alone. The
total cost of providing street lighting, including provision and maintenance of the electricity
distribution network and the street lighting equipment, is about 6 times4 the energy cost
alone. This brings the Australian total to about $M900 per year.
Environment
Street lighting affects the local environment (positively and negatively) by the provision of
wanted and unwanted light. The global environment is affected by greenhouse gas emissions,
and by the depletion of finite fossil fuel and other material resources.
4 Source: Reference 2: Coopers & Lybrand, “Report to IPART on Street Lighting Review” March 1988.
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Overview of Current Street Lighting Infrastructure
The Street Lighting Task
What Should be Illuminated?
Clause 2.1, General Objectives of AS/NZS 1158.1.1, 1997, clearly states :
“To accomplish these objectives, the lighting must reveal necessary visual
information. This consists of the road itself, the course of the road ahead, kerbs,
footpaths, property lines, road furniture and surface imperfections, together with
all road users including pedestrians, cyclists and vehicles and their movements,
and other animate or inanimate obstacles.”
Despite this clear statement, in practice there is a strong tendency of the standard and
designers to concentrate only on the lighting of the road surface and to neglect pedestrian
traffic and precinct areas, etc.
Even a casual reflection on this situation will reveal that this is far from an ideal situation. Of
all the objects which can be illuminated, the horizontal road surface probably presents the
least hazard.
How are the Street Lighting Areas Classified?
The current series of Australian/New Zealand Standards AS/NZS 1158 recognise three
categories of lighting systems, and these may be broadly described as follows :
Category V Applicable where the visual requirements of motorists are dominant
Category B
Category C
For roads and other public thoroughfares where the needs of pedestrians
are dominant
How Should these be Illuminated?
Light direction
The current edition and prior editions of AS1158 have only used horizontal illuminance5 as
the illuminance criteria.
The use of horizontal illuminance is an understandable expediency, as:
• measuring the horizontal illuminance requires only a single measurement at each point,
whereas vertical illumination necessitates also deciding in which direction to make the
measurement, and recording both the direction and the measurement, and
• it is a natural extension of the practice of measuring horizontal illuminance which is relevant
in office and other workstation lighting, where the work (writing, equipment, etc) is
horizontal.
But horizontal illuminance is a very poor indicator of the amount of useful light upon an
object such as the human body. Horizontal illuminance would be a good indicator of an
objects visibility from a helicopter, but not from the viewpoint of a motorist or pedestrian.
Good street lighting requires good vertical illumination, preferably from more than one
direction (please refer to Appendix 2).
5 Please see the Glossary on page 34 for a description of the key lighting terms used in this report.
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Which Lighting Equipment Should be Used?
Overview
The answer to this question lies partly in the answer to the previous one (light direction), and
partly in:
• the desired colour of light (governed by lamp type).
• the desired distribution of light (lantern characteristics:
_ lamp
_ reflector
_ diffuser / refractor)
• the desired brightness
• the desired operating hours (control device, usually a photo-switch but sometimes
methods such as ripple control are used).
• mounting options (usually existing power poles but sometimes dedicated
lighting poles).
• cost factors (energy, maintenance, capital cost, economic life, etc.)
Is Lighting Colour Important?
The colour of light, and especially light from artificial sources, varies widely: from the
“warm” glow of candlelight to the very blue light of the mercury vapour lamp and its
derivatives (tubular fluorescent and metal halide). But not all lighting colours are equally
suitable for all lighting tasks, and this is especially true of most street lighting applications.
To fully understand this matter it is necessary to have an understanding of how the human
vision system operates under various lighting conditions.
The human vision system
The human eye has the ability to adapt to ambient lighting conditions in both daylight and
night-time conditions; from over 100,000 lux to much less than 0.1 lux ( a ratio of more than
one million to one). If there is a lot of available light, for example in a well lit office or out
of doors in the day time, this condition is described as Photopic Vision which means light
adapted. Alternatively if the eye is operating in night-time conditions it is described as having
dark adapted or Scotopic Vision.
However there is an in-between adaptation situation described as Mesopic Vision, and the
lighting conditions on most of our main roads asks the human eye to operate within this
Mesopic Vision range. The human eye is using mesopic vision when the ambient “light
level” is between about 0.1 lux and 10 lux.
Why is this important? It must be remembered that luminance is a physical parameter which
can be measured by an appropriate photometer, but what the human eye percei ves is the
sensati on of bri ghtness6.
6 Key lighting terms used in this report are defined in the glossary on page 34
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Light colour and vision
The relationship between luminance and brightness is very dependent upon the colour of the
light source.
Under mesopic vision conditions, the luminance (measured value) and the brightness
(perceived value) of a surface under a blue white light source, is much more closely related
than when under an orange-red light source. The eye finds light at the blue end of the visible
spectrum much more useful than light at the red end of the spectrum. Light meters are,
however, calibrated for the eyes sensitivity to different light colours at much higher lighting
levels (ie. under photopic conditions).
Light colour and lighting design
The primary light parameter used in main road lighting is Luminance (candelas per square
metre). Table 2.1 of the Australian Standard AS/NZS 1158.1.1, 1997, Road Lighting, Part 1.1
Vehicular Traffic (Category V) Lighting, specifies values for this parameter for various
classes of roads.
However, the lamp / lantern performance data used as an input to lighting designs, and the
light meters used to assess the resulting lighting installation are based on the total light output
(lumens) and illuminance (lux) assuming that the eye will have the same response to the light
as it would at much higher lighting levels (eg. daylight, which could be over 100,000
brighter). This project team does not agree with such an extrapolation.
Light colour and lamp selection
Light at the blue end of the spectrum is more of an aid to vision under mesopic conditions,
and so this means that the mercury (blue white) based family of lamps is far more appropriate
for than is the sodium (orange red) family of lamps.
Unless the lighting or luminance values are very high and at least twice the values
recommended in Table 2.1 of AS/NZS 1158.1.1, 1997, people will not be using photopic
vision.
At the lower luminance (scotopic and mesopic vision), the relationship between luminance
and brightness will not be the same as during photopic vision. The correlation which exists
for yellow-red light (including high pressure sodium lighting) brightness (visibility) during
the day will not exist at the lower luminance.
In other words, the yellow-red light is less effective in aiding vision at low lighting levels,
and so much of the light produced is effectively wasted.
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Other Equipment Selection Criteria
Lamp
We have described how colour is an important factor in lamp selection. Other factors are:
• efficacy; how much electricity is required to produce the light.
• lumen maintenance; how well is the lamp efficacy maintained throughout the lamp’s life.
• lamp life and reliability.
• initial cost.
• physical considerations; size, robustness, lamp holder type, etc.
Lanterns
We have already described the need for street lighting to illuminate vertical surfaces well,
and this will influence the selection of lanterns. Other factors affecting the selection are:
• efficiency:
_ light output ratio (LOR); what portion of the light produced by the lamp actually escapes from the
fitting,
_ suitable distribution of light, and
_ control of intrusive and upward light.
• service life expectancy,
• maintenance (how easy is cleaning, lamp replacement, photo-switch replacement), and
• capital cost.
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How Does the Present Street Lighting Infrastructure Rate?
Light Colour
minor roads / residential streets
In Victoria, most minor road lighting is provided by the fluorescent coated ellipsoidal
mercury lamps. Its colour is acceptable, in that its spectral content is mainly at the blue end
of the spectrum.
The fluorescent lanterns used to light NSW minor roads would also be biased toward the blue
end of the spectrum, though because of the greater selection of tubular fluorescent lamp
coatings, the light colour can vary widely.
major roads / traffic routes
In both NSW and Victoria, some major road lighting is provided by mercury vapour lamps,
but the majority is provided by sodium lighting. There is also a continuing trend to replace
mercury vapour lighting with sodium lighting. We strongly recommend against this move.
(Note: While we are convinced of the correctness of this stance, both by
lighting science and our own observations, we understand that other people
in the lighting industry will not be persuaded easily. Therefore, we believe
field demonstrations will be required. This is discussed on page 21.)
Light Distribution
Vertical illumination and efficiency
The present system design and performance is a result of the concentration on horizontal
illuminance. As already discussed, this is not a useful parameter by which to judge street
lighting quality.
On main roads especially, providing vertical illumination while controlling glare is a
balancing act. There are conflicting requirements of controlling glare, by designing the
lantern light “cut-off” and illuminating vertical surfaces. Reducing lantern spacing and
increasing mounting height both help, but both incur additional capital costs.
However, a reasonable portion of the light produced by most minor road lighting
(mercury vapour B2224 refractor lantern or “flower pots” and fluorescent lanterns) does emit from
the lantern as vertical light. However, this is not the result of sophisticated lantern design; it
is the result of almost no design which allows the light to go in all directions. And light going
in all directions has a cost:
• overall efficiency is reduced,
• light pollution (intrusive and upward light) is increased,
and so more electricity is required to achieve the street lighting task.
Glare
The existing minor road lanterns present a significant visual distraction in that there is either
an exposed fluorescent lamp (NSW) or a high brightness refractor (Victoria) in clear view.
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Upward and intrusive light
Upward light pollution makes astronomical observations more difficult, degrading the
experience of both keen and casual observers. While there will also be light reflected upward
from roadways and other objects, reducing direct upward light will clearly assist in reducing
the problem. Also, direct upward light is wasted light, and so reduces the efficacy of the
street lighting system.
The reflector based HID lanterns used on main roads do not present an upward light problem
and do not normally create obtrusive light.
The refractor based mercury vapour lanterns used in Victorian minor roads, and their
f luor escent count er par ts in NSW pr oduce a si gnif i cant am ount of unnecessary upward l i ght.
Efficiency
Lamp efficacy – sodium vapour lighting
Sodium lighting has a high initial efficacy (lumens per Watt) and a high lumen maintenance
(i.e. efficacy stays high throughout the lamp life). However, these lumens are of little real
benefit if they register only on lux meters and not in peoples’ eyes.
When people go out onto the streets at night, they take eyes, not lux meters
Although mercury vapour lighting has acceptable colour, its low efficacy in terms of lumens
per Watt is not acceptable in today’s more energy conscious world. Even when new, the
efficacy of an 80 Watt mercury vapour lamp is under 50 lumens per Watt, and the efficacy
will degrade continuously throughout the lamps service life.
New Technology Fluorescent Lamps
The technology of fluorescent lamps has advanced considerably since the development of the
lamps now used in NSW minor roads lanterns. Even in the decade since Victoria replaced
most of its fluorescent street lighting, the technology improved greatly:
• lamps with a rated life of up to 24,000 hours are now available, compared with 8,000 for
fluorescent lamps of ten years ago and 12,000 for mercury vapour lamps.
• colour rendering has improved.
• efficacy has improved to as much as 100 lumens per Watt for lamps of over 30 Watts.
Therefore, judgement of modern fluorescent lighting should not be based on memories of
fluorescent lamp technology of the 1960s and 1970s, or even the 1980s.
In other words, old NSW fluorescent street lighting should not be compared with modern
alternatives without also considering modern equivalents of tubular fluorescent and compact
fluorescent lamps. This is discussed further on page 15.
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Time control
Street lighting should operate when it can make a contribution to visual amenity, and not
when it can’t. Street lighting control is achieved by photo-switches in Victoria and a mix of
photo-switch and electricity mains signalling (“ripple control”) in NSW. There is a trend to
replace ripple control with photo-switch control, and we expect this trend to continue.
The standard street lighting photo-switch uses a cadmium-sulphide cell. This device can be
installed in the casing of a single lantern or can be used to control a group of lanterns by
switching the power in a dedicated street lighting conductor or “fifth wire”.
The cadmium sulphide photo-switches have several disadvantages:
• they have a rated service life of only 7 years.
• they have a switch-off illuminance of three to five times the switch-on illuminance.
Thi s me a ns t h at i f t he d e si re d s wi tc h -o n il l umin a nc e is se t c or re ct l y, t h e swit c h- of f t ime wil l b e
s ig ni fi c an tl y l at er th an ne ed ed (a dd i ng a bo u t 15 mi nu te s 7 to t he da il y o pe ra t in g time).
• the switch-on setting is typically in the range 30 – 60 lux, which is much higher than the
ambient illuminance at which the street light can make a contribution to vision.
This unnecessarily adds about a further 20 – 30 minutes3 per day to burning time.
• the switch on setting drifts by about 10% per year, causing the lights to switch on even earlier
and off later. By the end of the 7 year service life, the switch-on point and switch-off point
will both have doubled. Again, this will add to unneeded burning time (about another 15
minutes3 per day, averaged over the service life of the photo-switch).
• they consume about 2 Watts when the lights are turned off. This is not a large power draw,
but it is unnecessary.
There is an alternative: electronic photo-switches, which are discussed on page19:
7 the times described in this section are indicative, being based on readings in Melbourne only, and only during
May. A more definitive analysis of the effects of control changes would require further simulation and
calculations, and is beyond the scope of this report. However, a more definitive study would not alter the
conclusions in this section of the report.
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Overall Street Lighting Assessment
Service quality
Minor road lighting (mercury and fluorescent) generally has acceptable colour and a
reasonable portion of the total light is delivered as vertical illumination
Major road lighting generally has a red-orange colour which is unsuitable for night vision.
Efficiency
The efficacy of mercury vapour lamps is unacceptably low, and this is further degraded by
the inefficiency of the lantern – refractor.
The LOR of most major road lanterns is acceptable, but the overall effectiveness of the
lighting is low, because of the poor response of the eye to the light colour.
The lighting system is also degraded by its unnecessary operation, caused by inaccurate
photo-switch control.
Potential
These shortcomings provide the potential to improve street lighting quality (safety, amenity,
etc.) while also reducing financial and environmental costs. A win-win situation. The fact
that these improvements can be made now, when significant capital expenditure is required
anyway, makes the potential easier to achieve.
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Overview of Best Practice Street Lighting
Australia and New Zealand
New Australian New Zealand Standards :
A new draft of an Australian/NZ Standard for residential areas has recently been prepared
and is presently under public review. It is called AS/NZS 1158, Part 2, Pedestrian Area
(Category P) Lighting. This draft differs from the old AS 1158.1-1986 in that all lighting for
residential roads, pathways and circulation areas will be designated Category P, replacing the
older B and C Categories.
A copy of an article by Fisher and Rogers printed in the May 1999 edition of “Lighting,”
Vol.19, No.3, discusses the changes from Categories B and C to Category P, and is appended
(Appendix 2) for your reference. As stated by the authors in their summary, this is a major
revision of the Standard in relation to lighting for pedestrian traffic.
The major change is the inclusion of a vertical illuminance parameter, but while this is a
useful criterion it is also very simplistic. In our opinion the inclusion of semicylindrical
illuminance (Ehz) would have been far more meaningful for situations involving the
modelling of people. (Appendix 2 refers).
Another concern we have is that the illuminance values quoted in the table of “Values of
Light Technical Parameters for Roads in Local Areas and for Pathways” are very low, and
we have grave doubts as to the easy availability of photometers to accurately measure these
small values.
This is particularly so because the currently used HPS lamp is strongly biased towards the
orange-red end of the spectrum, while in a similar manner the metal halide lamp is strongly
skewed towards its blue end. These are the colour bands in which the greatest errors will
occur if a conventional photopic-calibrated lux-meter is used.
Lighting for Main Traffic Routes :
The current road lighting practice as set out in the Australian New Zealand Standard AS/NZS
1158.1.1-1997 (Category V) follows European practice rather than the IESNA (North
American) methodology.
The European practice has evolved from a framework developed over many years by the
Commission Internationale De L’Eclairage (CIE), much of it under the guidance of Dr. A. J.
Fisher of Sydney, who is the current Chairman of the Standards Australia Road Lighting
Committee LG/2.
The European Committee for Standardisation (CEN) produces European road lighting
standards which also follow the CIE guide-lines, and so it would be very difficult to make any
major break from the principles of AS/NZS 1158. Minor changes depending on local factors
are possible, but probably not any national change.
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International
This sections gives a brief description of street lighting practice and trends. A more detailed
description is in Reference 5 (page 23).
North America
Summary
The trend in North America is toward street lighting standards based on performance,
assessed according to the visibility of a standard small “target”8. We agree with this move
from an assessment of lighting based on simple and inappropriate parameters such as
horizontal illuminance.
Description
The current IESNA9 recommended road lighting design method is based on the use of either
illuminance or luminance10, but this body is now developing a standard based on visibility.
Of course, this means that the road lighting design aim will be more closely aligned with the
goal of road lighting: to make objects visible. This is a very sensible aim, but a very big task.
With a system based on horizontal illuminance, the focal point of creating the standard is
deciding on a value for that single parameter, for a limited number of situations. However,
with standard based on assessing visibility afforded by the lighting system it is necessary to
decide:
• which factors will affect visibility, and
• how these will be assessed and incorporated into the standard.
The factors identified by the IESNA are:
• adaptation luminance,
• contrast between target and background,
• veiling luminance,
• target size,
• observation time, and
• observer age.
These factors each hide a wide range of options. For example, observation time will clearly
be dependent on the speed of the observer and the “target”. And if the observer is a motorist,
the greater the speed, the more warning is required, and so the target needs to be visible from
a greater distance. Target size could represent a black cat, a child, an adult, a cyclist, or some
other object, or could represent range of targets. Observer age is also a sweeping
simplification; not everyone of the same age has the same visual ability.
8 “target” refers to a visual target, but given that the device represents a pedestrian, it is a poor word choice.
9 Illuminating Engineering Society of North America
10 please see the glossary on page 34
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There are other factors which could be considered such as:
• the difficulty of the driving task (some roads present more hazards and distractions than
others).
• the position(s) of the target with respect to the observer (on the road, on the kerb, etc.).
Once such a standard is written, performance of road lighting systems need to be assessed
according to the standard. This can be done using:
• computational methods,
• measurement using CCD technology developed for video cameras.
Relevance
We believe that the trend towards this performance assessment based design strategy will
continue in North America and be adopted in other countries. Australia needs to watch and
participate in this process.
Europe
Developing European street lighting standards involves ensuring that the standards are
relevant and acceptable to the member countries. Within this environment, the process
focuses on producing a framework for designing lighting systems appropriate to local needs.
The four main activities are:
• classifying the lighting situation based on factors such as:
• weather types in that location,
• type of road (eg. divided carriageway, number of lanes),
• vehicle speed,
• background visual complexity.
• deciding on the performance required of the lighting system for each road classification.
Lighting performance for main roads is based on the silhouette principle, and horizontal
luminance is still the main parameter.
For pedestrian areas, more complex and subtle performance measures are also specified,
including semi-cylindrical illuminance (see page 32) hemispherical illuminance and vertical
illuminance. This is particularly relevant to some countries where very low mounting height
lanterns are used, and achieving horizontal illuminance between the lanterns is almost
impossible. With the trend to under-grounding of electricity cables, this will become more of
a consideration in Australia.
• calculation methods, and
• assessment methods.
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Street Lighting Recommendations
Equipment
Available Light Sources
The progression of electric lamps for street lighting application has broadly followed the
historic development of the electric lamp. The first lamp type to be used was the incandescent
filament lamp, and this was followed by the early mercury MA and MB type lamps and the
low pressure sodium lamps.
Later replacement of the incandescent lamps with tubular fluorescent lamps for both main
roads and residential streets was the next development, and in more recent times these
fluorescent lamps have again been replaced by mercury vapour (in Victoria) in lamps of a
variety of wattages, and in many main roads by high pressure sodium lamps.
The most recent developments in lamp technology, apart from the Sulphur or Induction
lamps, has been in small watt metal halide and compact fluorescent lamps, but to date neither
of these lamp types have had wide application in street lighting.
This wide variety of available lamps suggests that it is not unreasonable to question whether
or not one type of lamp is better than another.
Comparing Light Sources
As shown in Appendix 3, there is a number of discharge lamps available which have a lumen
output approximating that of the 80 Watt mercury fluorescent lamp. All of the lamps shown
in Appendix 3 may be considered as long life, when compared to the life of GLS
incandescent or Tungsten Halogen lamps. Both of the values; life and lumen output must be
viewed with a certain degree of caution, since some manufacturers tend to be conservative in
their claims in order to minimise criticism of the performance of their products, while others
are more optimistic.
The technical reason for this is based on an assumption about when a batch of lamps is
considered to be at the end of its life. The conservative school of thought claims the average
life is when 20% of the lamp batch has failed, while the optimistic school says that this point
is reached when 50% loss is noted. It is therefore obvious that the conservative group will
show a shorter lamp life when compared with the latter group.
Similarly there are several methodologies used for determining the lumen output of lamps so
the two groupings of conservative and optimistic are also evident here, but general consensus
takes the lower (conservative) figure of approximately 3400 lumens for the average 80 Watt
mercury vapour fluorescent lamp.
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Each of the lamp types listed in Appendix 3 has weaknesses, as shown below :
• The single ended mercury Halide Group 1 lamps have G type bi-pin bases which do not cope
well with rough service or vibration.
• The Group 2 HPS lamps in general, but especially the 50 Watt version, have poor colour
renderings and tend to badly distort all colours and especially skin colourings.
• The CFL Group 4 lamps tend to be physically large, and again use pin type electrical
connections which suffer from vibration unless fitted with specially designed bases to support
the lamps. While this is acceptable, it makes lamp replacement a slower process.
Another lamp that has been recently introduced to Australia is the 16mm diameter tubular fluorescent
lamp known as the T5. A similar 14 Watt version (549mm long) produces 1220 lumens which is
approximately 10% more than that from the old 26mm, 18 Watt lamp for a lower Wattage.
The main disadvantage of the tubular lamp for street lighting is that the lumen output of the
lamp is considerably reduced when the ambient temperature is low, and this could be of
serious concern in Tasmania, some parts of Victoria, and in other “high country” areas under
consideration. However, the 14 Watt T5 tri-phosphor lamp is understood have overcome this
problem, and will soon be trialed in NSW.
Lamps for the Lighting of Residential Streets
Recommended
Considering the requirements of efficacy, colour, and life, it is our considered opinion that
the most appropriate light sources for residential streets are:
• the 35 Watt metal halide lamp with a blue white spectrum, and
• compact fluorescent lamps, also with a blue-white spectrum.
The most appropriate for a given situation will depend on factors such as mounting
restrictions (eg. existing poles, new installation, spacing).
A single 35 Watt metal halide lamp in a lantern with appropriate photometric characteristics
will replace a standard 80 Watt mercury vapour lantern. This will result in improved
illumination quality and a power saving of at least 54% (details on page 20).
Compact fluorescent street lighting lanterns are discussed on page 17.
Watching brief
Another lamp type which is very promising is the 50/35 Watt Osram Citylight. This is an
acceptable lumen package which gives good colour rendering, good lumen maintenance, and
the option to switch to a lower wattage (from 50 to 35). However, this lamp type is so new
that we recommend further experience be gained with the lamp before large scale
installations are contemplated. Small-scale trials however are recommended (please see page
21).
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Lamps for the Lighting of Main Roads:
In general and at this time, the most commonly used ranges of lamps for main roads are the
high pressure sodium or mercury vapour 250 and 400 Watt units with occasional use of the
150 Watt lamp. As shown in Appendix 3, the metal halide lamp has more than a 30% higher
efficacy than the mercury fluorescent lamp and the use of this lamp would give a 30%
increase of light on the road surface.
A change from mercury vapour to metal halide lighting will result in a significant reduction
in energy consumption, e.g.: by replacing a 400 Watt mercury lamp lantern (19,000 lm and
circuit power of 425 Watts) with:
• a single 250 W metal halide lamp (20,000 lm) 268 Watts total saving 37%
• 2 x 150 mWetal halide lam(p2s4,000 lm)336 Watts tsoatvailng 21%
The savings with a single 250 Watt lamp are higher, though there may be other advantages in
using two 150 Watt lamps, either in a single lantern or as two single-lamp lanterns, such as:
• more even illumination,
• less glare, by facilitating closer lamp spacing or greater mounting height and greater light “cut
off”,
• simple “lumen set-back” by switching one lamp,
• greater reliability, as half lighting will be available in the event of one lamp failing or the arc
extinguishing.
Lanterns for Lighting Minor Roads
Metal halide
We have modelled the performance of an efficient minor roads lantern based on photometric
test results for a GEC / SLI11 brand “Urban Minor” model lantern. This shows that the
combination of this lantern and a 35 Watt metal halide lamp will produce better illumination
than the present GEC model B2224, 80 Watt mercury vapour lantern which is used throughout
Victoria.
Compact fluorescent
In order to select a lamp configuration for minor roads, we have relied on first principles. The
calculated results can then be used as a “market pull” to encourage manufacturers to supply
appropriate lanterns. Given the size of the market and discussions with manufacturers, this
approach should be successful.
11 Sylvania Lighting Industries
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What light output is required from the street-light’s lamp(s)?
The required lamp light output can be calculated by:
• starting with the light output of present street lighting lamps, and
• reducing this figure according to the higher efficiency of modern street lighting fittings in
delivering the light from the lamps to the area requiring illumination.
Light produced by an 80 Watt mercury vapour lamp 3400 lm
The existing minor roads lanterns using a refractor glass diffuser with
inherent light loss, and an overall indicative LOR of
60%
And so the amount of useful light which leaves the lantern is 3400 x 60% 2040 lm
We expect a modern, efficient lantern with a clear lens and efficient reflector
to have a LOR of:
80%
And so the next generation of minor roads lanterns will require a lamp output
of: 2040 lumens divided by LOR of 80% 2550 lm
Referring to the table in Appendix 3 (page 29), at the lowest power, a suitable fluorescent
lamp for a lantern to directly replace the current 80 Watt mercury vapour, is a single 36 Watt
compact fluorescent lamp (2800 lumens).
Lanterns for Lighting Main Roads
Because of relatively small changes in lamp technology in recent years, there has been only a
small change in the development of lanterns for main road lighting.
Similarly there are only a limited number of suppliers in this country at present, but perhaps
if restrictions were eased there could be a market opened up to overseas suppliers, some of
whom have already shown interest.
Ballasts
Street lighting should use electronic ballasts, because of the higher efficacy and the
lengthening of lamp life. However, there are no reasonably priced and readily available
electronic ballasts available for discharge lamps. This is a chicken and egg situation: suitable
electronic ballasts are not available because there is insufficient market demand, and the
demand is low because of pricing and product availability. Pricing is also directly related to
sales and production volumes.
The large scale re-equipping of minor roads street lighting in NSW and Victoria brings the
opportunity to overcome this barrier. We recommend that SEDA and SEAV facilitate a local
manufacturer to equip for the volume production of electronic ballasts to suit the compact
fluorescent and HID lanterns described in the preceding pages.
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Lighting Control
Electronic (also called solid “state”) photo-switches with silicon diode sensors are preferable
to cadmium sulphide cells (described on page 10) because they:
• have a rated service life of 12 years, reducing both labour and vehicle costs, and improving
lighting system reliability.
• have a switch-off illuminance which is independent (including lower than) the switch-on
illuminance.
• are available with a standard switch-on settings of 10 lux, reducing lighting times by about 20
minutes per day compared with a 30 lux level. Further, a lower switching level could be
ordered for purchases of large batches.
• have a switch on setting which is stable over the life of the photo-switch.
• consume negligible power.
Electronic photo-switch cost – benefit
The maintenance savings alone justify the price premium of electronic photo-switches.
Assuming that replacing a photo-switch costs $70 ($50 for truck and labour, $20 for call
centre, purchasing and other administrative costs), the annual cost of standard and electronic
photo-switches is:
Photo-switch
Type
Initial Cost Life Total replacement
cost
photo-switch
maintenance cost
$ years $ each time $/year
Standard $9 6 $79 $13.17
Electronic $15 12 $85 $7.08
So electronic photo-switches are justified even without considering the benefits of energy
savings and increased lamp life.
An electronic photo-switch will reduce lantern burning time by an hour per day, and so will
increase the interval between lamp replacement by about 10%.
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System Costs and Benefits
Minor roads
The following is a comparison of the costs and benefits of a standard 80 Watt mercury
vapour street lantern and the proposed 35 Watt metal halide light:
Before After
Fitting B2224 “Urban Minor”
Lamp type mercury vapour metal halide
Capital Cost $65 $80
Photo-switch upgrade $0 $6
Ballast upgrade $0 not included or estimated12
Total capital cost $65 $86
Lamp Watts 80 35
Ballast Watts 16 8
Circuit Power Watts 96 43
Energy Use
Burning time hours/year 4,335 4,000
Lantern kWh/year 416 172
Photo-Switch kWh/year 9 0
Total kWh/year 425 172
Reduction in energy use n/a 60%
Energy cost / year $/year $34.00 $13.76
Energy Saving $/year $20.24
Maintenance
Initial cost premium ## $15.00
Annual return on initial premium % p.a 74%
Appendix 4 shows that the Urban Minor also delivers more even illumination than does the B2224.
Notes:
# We have estimated a medium term electricity price (weighted average peak and off-peak) of 8 cents
/ kWh, including energy and DUOS and NUOS charges. This differs from the IPART approach of
assigning a value to each component (Reference 2).
## The cost premium does not include the additional cost of an electronic photo-switch, as this
premium is already justified by the lower cost of maintaining the photo-switch.
We have not included the benefit of longer effective lamp life. The mercury lamp has a
shorter effective life than a metal halide lamp, because it will reach an unacceptably low
efficacy sooner. Of course, the mercury lamp could be left in service for longer than a metal
hal ide lamp, as it wi ll oft en last many years without fading completely. However, it’s light output
at that t ime wi ll be unacceptably low and the quali ty of street light ing unaccept ably poor.
12 The price will be very dependent on production volumes and the street lighting market could change the
production volume significantly. There is the potential to reduce electronic ballast prices sharply with street
lighting projects.
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Implementation
We do not expect or anticipate that this brief overview will, by itself, dramatically change
Australia’s one billion dollar a year street lighting industry. Indeed, we expect that our
conclusions will be challenged by many people in the industry, and we hope that this will
prompt further discussion and exploration of what the community expects of street lighting,
and how this can best be achieved.
We are aware of at least some undertakings which will assist this process:
Field Trials
We strongly recommend that field trials of various street lighting lanterns be conducted with
the cooperation of suitably interested electricity distribution businesses and local
government. Such trials will serve to:
• allow people to judge street lighting with their own eyes,
• provide an opportunity for innovative manufacturers to demonstrate their wares,
• refine new hardware, including modifying design with the aim of minimising installation
time, etc
• render tangible some of the abstract concepts described in this report, and so democratise the
process of developing new street lighting systems by facilitating comment by lay people as
well as lighting professionals,
• facilitate the involvement of appropriate groups (eg. IESANZ, road safety and research,
electricity industry, local government, Standards Australia, etc).
Similar trials / demonstrations were conducted in Sydney in the 1960s, and were known as
the “Beecroft Road experiments”.
Industry Facilitation
We recommend that SEAV and SEDA consider facilitating Australian industry’s
development of efficient street lighting lanterns which “push the envelope”. This need not be
an expensive undertaking, indeed we do not recommend any direct subsidy. Instead we
envisage acting as a catalyst, by bringing together potential equipment purchasers (local
government and electricity distribution network companies) and manufactures, to form
buying contracts and volumes which will make the energy efficient equipment viable for both
groups.
Representation on Standards Committee
We believe that SEAV and SEDA should lobby Standards Australia to influence a future
revision of AS/NZ Standard 1158.
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Further Investigation
The Installation of Lighting Systems :
Currently roadway lighting systems are very stereotyped and there appears to be very little
room to move as far as change is concerned.
Some common European practices such as Catenary lighting13 have never been adopted in
this country, and we would suggest that it might be time to revisit this particular
methodology.
With the easy availability of large Elevator Platform Vehicles the opportunity for greater
mounting heights and wider spacing of lanterns is now possible, and we believe that these
should certainly be considered. Obviously this practice would reduce the number of
poles/lanterns required per kilometre, and so achieve a greater saving of energy. The
appearance of the urban streetscape could also be enhanced.
Since few manufacturers presently produce lamps with a Wattage of between 400 and 1000
Watts, the use of multiple heads of lamps eg. 3 x 250 Watts or 2 x 400 Watts may be worth
considering.
In our opinion, opportunities for savings in energy and capital installation costs will
come through the reduction of the number of poles and lanterns provided in any given
installation. This concept can be achieved by significantly increasing the presently used
mounting heights of the lanterns, and we believe that this recommendation should be
fully explored.
Hardware Choice
In current practice the number of types of lanterns used is restricted on the grounds of
limiting the number of spares to be held in store. Similarly HPS and MV lamp types and their
Wattages have been restricted to a narrow range in the pursuit of standardisation.
While these policies may have had some justification in a large organisation as seen in the
older State Electricity Commission, we believe that in the smaller organisations in vogue
today in the form of the Distribution Businesses, greater flexibility should be possible.
Distribution Businesses claim to have policies with regard to added service and value adding,
so the general public should therefore be able to expect better quality service and more
evident concern regarding environmental protection and the need for the conservation of
energy.
Demonstration of these concerns could be shown by the purchase and use of better quality
photoelectric daylight switches for use with the present lanterns, so as to avoid their burning
long after they are required.
It is hoped that with contestability will come not just choice by price or tariffs, but also the
offering of a wider choice of equipment in such things as lamps and lanterns. It is also hoped
13 Catenary lighting means lighting provided by lanterns attached to a horizontal suspension cable.
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that this contestability will bring about a reduction in maintenance costs and an improvement
of services offered to the general public.
Maintenance :
We understand that the decision as to who is to be responsible for the maintenance of the
public lighting system has not been made and is still under discussion. In the years following
World War 2 the street lighting administration for the Melbourne metropolitan areas was
centralised at the Rooney St Richmond Depot, and patrolling officers from this depot were
responsible for the maintenance of this system.
It is clear that this system has now gone forever, but given the importance of street lighting
within the community it is essential that a similar service level should be resumed. If the
general public was encouraged to report malfunctions of the system to a toll free telephone
number, surely in these days of the all embracing computer a return to such a service level
should not be too difficult.
References
1 Electricity Supply Association Australia “Electricity Australia 1998″
2 Coopers & Lybrand in association with Worley Consultants
“Report to IPART on Street Lighting Review” March 1988
3 Australian / New Zealand Standard AS/NZS 1158.1.1, 1997 Public Lighting
4 Sustainable Energy Authority, Report: “Street Lighting and Contestability” Author Paul Rogers, January
1999.
5 Lighting Magazine, September 1998, Article “Lighting for Safer Roads on Three Continents” pp 40-45.
Lewin, Simons and Grundy
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Appendix 1: NSW Fluorescent Lanterns
Lantern inventory
According to Reference 2, the number of fluorescent street lighting lanterns under the control
of the NSW electricity distributors is:
Electricity Distributor Advance
Energy
Australian
Inland
Energy
energy
Australia
Great
Southern
Energy
Integral
Energy
North
Power
Total
Total Lanterns 30,612 3,089 343,850 38,566 173,379 60,493 649,989
Fluorescent portion of
total lanterns
43% 56% 69% 40% 57% 51% 61%
Fluorescent lanterns 13,163 1,730 237,257 15,426 98,826 30,851 397,253
The fluorescent lanterns are programmed for replacement now. If NSW adopts the same
solution to fluorescent lantern replacement which Victoria took, the capital and recurring
costs will be about:
Capital cost
Cost each Total
Fluorescent lanterns 397,253
Replacement lantern cost (e.g. B2224 MV 80 Watt) $65 $M 25.8
Installation cost (Labour, truck, etc). $100 $M 39.7
Total cost, supply and install $175 $M 65.5
Recurrent cost
Based on replacement of each fluorescent lantern with an 80 Watt mercury vapour fitting
(circuit power 100 Watts), the recurrent energy consumption and total cost using
recommended (Reference 2) IPART electricity pricing would be:
Distributor Advance
Energy
Australian
Inland
Energy
energy
Australia
Great
Southern
Energy
Integral
Energy
North
Power
Total
Fluorescent
lanterns
13,163 1,730 237,257 15,426 98,826 30,851 397,253
Installed demand,
based on 100W each
MW 1.32 0.17 23.73 1.54 9.88 3.09 39.7
Energy use,
based on 4000 hr/ yr
GWh/yr 5.27 0.69 94.90 6.17 39.53 12.34 158.9
Lighting Charge $/MW.h
14
$210 $210 $210 $210 $240 $240
Annual Charge $M/year $M1.11 $M0.15 $M19.93 $M1.30 $M9.49 $M2.96 $M34.9
14 The NSW street lighting cost recovery method converts all fixed and operating costs to an “equivalent” charge
per unit of energy consumed. While the project team does not agree with this methodology, it is used here for
consistency.
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Appendix 2: Magazine Article, New Street Lighting Standard
The following article is reproduced from the May 99 edition of “Lighting” magazine.
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Appendix 3 Lamps Comparison
Lamps for minor roads / residential streets
Group Type & Nomenclature Power
(Watts)
Brand
(example)
Output
(lumens)
Efficacy
(lm/Watt)
Osram 3400 42
1. Mercury MBF/U 80
Thorn 3850 48
a) Single End HCI 35 3400 97
b) HQI 70 5500 79
50/35 4500 /
2500
90 /
71
2. Metal Halide
c) City Light DS
80/50
Osram
6100 /
3400
76 /
68
a) NAV 50 50 3500 70
b) NAV 70 70 5600 80
c) NAV 50 Super 50 4000 80
3. High
Pressure
Sodium
NAV 70 Super 70
Osram
5000 71
a) DULUX T 26
(2 x 26)
1800
(3600)
69
b) DULUX T/E 42 3200 76
4) Compact
Fluorescent
Lamps
c) DULUX F 36
Osram
2800 78
a) Standard
26 mm diameter
18 Osram 1100 61
5) Tubular
Fluorescent
Lamps b) tri-phosphor “T5″
16mm diameter
14 Osram
“lumilux plus”
1220 87
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Appendix 3 Lamps Comparison (continued)
Lamps for major roads / traffic routes
Group Type & Ellipsoidal Lamp Tubular Lamp
Nomenclature
Power Output Efficacy Output Efficacy
(Watts) (lumens)(lm/Watt) (lumens)(lm/Watt)
1. Mercury Deluxe 250 14,000 56
400 24,000 60
2. Metal Halide (Coated) 250 19,000 76 20,000 80
400 32,000 80 42,000 105
3. High Pressure Sodium 250 25,000 100 30,000 120
400 47,000 117 54,000 135
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Appendix 4: Comparison of Two Minor Road Lanterns
The following charts show the calculated isolux plots for two street lighting lanterns using
the same lamp and the same spacing. The lanterns are:
• the B2224 “flower pot” which is the standard minor roads lantern in Victoria, and
• the “Urban Minor”
B2224
Urban Minor
The comparison shows that the Urban Minor provides more even illumination.
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Appendix 5 Semi-Cylindrical Illuminance:
In 1992 the CIE published a document entitled “Guide to the Lighting of Urban Areas”,
Publication No.92. This recommends that semi-cylindrical illuminance be the preferred light
technical parameter to adequately illuminate vertical surfaces, and in particular, the human
face.
Semicylindrical illuminance is also the preferred parameter in some Nordic countries where
lanterns with low mounting height or bollards are extensively used. These types of lanterns
tend to have a poor distribution of horizontal illuminance, but quite satisfactory vertical
illuminance.
Earlier studies undertaken in Russia and more recently in Australia, have shown that semicylindrical
illuminance is a much more acceptable indicator than horizontal or vertical
illuminance of the adequacy of lighting in non task areas such as public spaces, railway
stations and public buildings.
We believe that this matter of vertical illuminance versus semicylindrical illuminance as
indicators for the true modelling of the human body and in particular the human face, should
be taken up with Standards Australia. Perhaps it should be considered by a joint meeting
between the Standards Australia Technical Committees LG/1 and LG/2. Should you wish us
to be a contributor to such a meeting we would be happy to oblige.
A Personal Note from Kevin Poulton.
I have taken a great interest in alternative illuminance parameters since the early 1960s when
the late Dr A. Dresler introduced mean spherical illuminance to us as his students at the
RMIT. This was a concept which he developed as an alternative to horizontal illuminance
during his research days at the Berlin University in the 1930s. In the 1960s the Russian
researcher M. M. Espaneshnikov published extensively on the application of the parameter,
mean cylindrical illuminance and showed that it was a more adequate indicator for revealing
the true shape of the human form than either horizontal or vertical illuminance. Later in the
early 1980s Stockmar and Haeger published an article on a calculation method for half or
semi cylindrical illuminance and this has since been adopted by both the Danes and the
Dutch for sports lighting and the lighting of pedestrian areas.
During the preparation time of the 1990 edition of AS1680, Interior Lighting standard I
carried out a series of studies to discover what was an acceptable value of ambient light in
non task interior spaces. Using mean semi cylindrical illuminance as the main parameter I
found below 100 lux was too low and above 700 lux was too high. Unfortunately the
Standards Committee would not accept this study and went back to the conventional
parameter of horizontal illuminance.
Thus historically there has been much research and support for the concept of cylindrical
illuminance but for some unexplained reason the Western world has been reluctant to adopt
this concept.
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The difference between semi cylindrical and vertical illuminance is a subtle one, semi
cylindrical illuminance has a significant “side lighting” effect which the vertical illuminance
has none. Semi cylindrical illuminance brings out the roundness, the three dimensionality of
the human form. It is easy to calculate and to measure.
Theoretically any visual environment has two components of illuminance, that is, there is a
direct component and an indirect or diffused component. The direct component come directly
from the lantern/s. The second component is the diffused component which is reflected from
adjacent surfaces or objects. In many interior spaces the diffused component is equal too, or
approaching the direct component, hence shadow patterns are very soft or even non existing.
However, in most exterior situations the diffused component is often negligible or
approaching this, hence as a consequence the dominant illuminance is very directional and
thus the strength of the light and shadows patterns is very noticeable.
Vertical illuminance values are very dependent upon the orientation of the subject, especially
the human head, with respect to the light source. This means that the vertical illuminance of
one face of a cube will be very high but on another face at ninety degree rotation could be
approaching zero. Yet these readings do not necessarily reflect the visual reality. In the case
of the human face, vertical illuminance does not take into account the roundness of this
object.
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Appendix 6: Glossary
Key lighting terms
The following key terms used in the report are arranged in a logical (rather than alphabetical
order)
lantern the term traditionally used for a street lighting luminaire, i.e. a complete
“lighting fitting” including the lamp, lamp holder, body, lens / diffuser, and
control components including ballast, power factor correction, and possibly
photo-switch.
illuminance a measure of the amount of light flowing from a light source incident on a
given area.
expressed in lux, where 1 lux = l lumen per m_ .
horizontal
illuminance
the illuminance measured by a meter in the horizontal plane, facing directly
up. This gives an indication of how much light is falling on a horizontal
surface.
vertical
illuminance
the illuminance measured by a meter in a vertical plane, facing in a specified
direction. This gives an indication of how much light is falling on a vertical
surface.
semicylindrical
illuminance
please see explanation in Appendix 4
luminance a measure of the amount of light reflected from an object, and so is
dependent on both the amount of light incident upon it (illuminance),
characteristics of the incident light (eg. colour) and the reflective properties
of the object (colour, gloss, surface texture).
brightness a term to describe the apparent or perceived amount of light on an object, and
so is dependent on:
• the illuminance incident on the object,
• the luminance of the object,
• glare, contrast, and other environmental factors,
• the position of the viewer,
• the viewer’s adaptation to the ambient light,
• the quality of the viewer’s vision.
Brightness is subjective as well as being influenced by measurable
parameters.
glare Unwanted light; light which interferes with vision or visual comfort.
LOR Light Output Ratio. The portion of the light produced by a lamp which
escapes from the lantern, expressed as a percentage.
SEDA and SEAV 35 Street Lighting Efficiency
file: 244 © Genesis Automation and Lightlab International June-99
Appendix 7: About the Authors
Geoff Andrews
Geoff is the founder and Engineering Manager of Genesis Automation, a company
specialising in reducing energy consumption while improving the of the energy services
delivered. He has specialised in the implementation of energy saving projects, including
overcoming the practical and institutional barriers which often impede the full achievement
of energy efficiency opportunities.
These services have been applied in a wide range of organisations including many local
governments, government, commercial and industrial customers.
Before Genesis Automation, Geoff worked as an in-house energy manager and then as an
energy efficiency consultant.
Kevin Poulton
Kevin is well known in the lighting industry, both as a professional lighting practitioner, a
teacher, researcher, and a leading light in the Illuminating Engineering Society of Australia
and New Zealand.
He has qualifications as both an architect and an electrical engineer.
Kevin is the founder of LightLab International, an Australian independent photometric
laboratory and consulting company providing services and equipment to many local and
international clients. This role includes designing and testing luminaires.
His street lighting design experience includes working for the SECV15 as a street lighting
designer.
15 The former State Electricity Commission of Victoria.

1
Two Centuries of Electric Light Source Innovations
Maxime F. Gendre
Eindhoven University of Technology
Department of Applied Physics
Group Elementary Processes in Gas Discharge
N-Laag, G2.04, 5600MB Eindhoven
e-mail: mfgendre@tue.nl
web site: http://www.geocities.com/mfgendre
Light, and ways of producing it, undoubtedly belongs to the most fascinating and exciting kind of science
man has ever tried to master. To be more exact, light sources do not belong to one kind of science but
embody most of them. This is the development of vacuum techniques, of particular glasses, the purification
of gases, the refinement of metals, the elaboration of fluorescent substances, and other countless
engineering feats that allowed the making and improvement of all lamps we depend on today. Of course,
many of these breakthroughs were precisely driven by the need for better light sources, having longer
lifetimes, higher efficiency and better color properties. Yet, no one suspects that two centuries of scientific
research, discoveries, developments and
refinements stare upon us every time we
flip a switch to give birth to light.
It was exactly two hundred and one
year ago that Humphry Davy set the
foundations of the lighting industry with his
simultaneous discoveries of light emission
from incandescent metal wires and from
electrical arcs (also by W. Petrov). Until
1802, and since 400,000 BC, man had
relied solely on fire for his lighting needs.
The invention of the electric pile by
Alessandro Volta in 1800 opened a brand
new era of perspectives. His stacks of
copper, zinc and saltwater-soaked
cardboards allowed the circulation of steady
flows of electric currents that would
eventually spark the lighting revolution. A
revolution that was indeed slow to start.
The early years
The discoveries of Davy and Petrov had to wait five decades, the development of steam-powered dynamos
and the refinement of Volta’s battery, before becoming a practical reality. By 1850, Léon Foucault built the
first carbon arc lamp that was subsequently used for theatrical lighting, while four years later Einrich
Goebel, a German emigrant in the USA, made the first practical incandescent lamps. His sources were made
of carbonized bamboo filaments enclosed in evacuated perfume bottles, and were intended to illuminate the
shop window of his watch shop in New York city.
A third way of electric lighting emerged in 1856 from the discovery by Michael Faraday (England) of
the electric glow discharge in rarefied gasses (1831-35). This year, Julius Plücker and glass blower Enrich
Geissler started some systematic investigations of electrical discharges in evacuated glass tubes provided
with electrodes at each end. Subsequent experiments from Hittorf, Crookes and Golstein revealed that the
light color of the discharge changed upon the addition of other gases and vapors. This phenomenon was
Figure 1: Luminous efficacy evolution of light sources.
1880 1900 1920 1940 1960 1980 2000
200
160
120
080
040
year
luminous
efficacy
(lm/W)
low-pressure sodium
high-pressure sodium
metal halides
low-pressure mercury
high-pressure mercury
Incandescent
major breakthrough
2
finally understood in 1859, when Robert Bunsen and Gustav Kirchoff showed that each chemical element
emits a specific set of light colors, or spectral lines. This discovery eventually set the foundations of
spectroscopy. However, the inner working principles of these tubes were not understood until the 1920s,
when General Electric (GE, USA) scientist Irving Langmuir studied and made the first accounts of the
physics of ionized gases, and coined the term plasma to describe them. Then for this reason and others,
“Geissler” and “Crookes” tubes were relegated to the rank of lab curiosities until the beginning of the
twentieth century.
Figure 2: Various ways of light production.
On the side of carbon arcs, many improvements followed the lamp of Foucault. From the work of Foucault
and Dubosc, Serrin designed in 1859 a mechanical system to keep the arc at a given position despite the
unequal burning rate of the cathode and the anode. Later, Crompton in England and Wallace-Farmer in the
USA made an arc lamp that was regulated in voltage, thus permitting its use in series circuits. A further
major step followed in 1870, when Russian engineer Paul Jablochoff invented a self-regulating arc lamp
made of two close graphite rods separated by a layer of plaster of Paris. These lamps had a lifetime of 90
minutes, and a set of electrodes could not be re-ignited once it has been used. Despite its many drawbacks,
this kind of source led in 1878 to the first practical electric arc street lighting in Paris. Two years later,
Compton and Pochin in England and Friedrich von Hefner-Alteneck in Germany invented the differential
carbon arc lamp, which was power-regulated by monitoring both arc current and voltage. This system
eventually superseded Jablochoff’s lamp in street and industrial lighting.
Carbon arc systems were pretty crude, cumbersome, noisy, dirty and drew a lot of electrical power.
Beside this, its bright harsh light did not make it suitable for home lighting. The consequence is that many
persons looked for a better and softer way of producing light, and it was already of common knowledge that
a piece of carbon or metal heated by a current would do the job. However, things sound far simpler than
they are, and most of the attempts went up in smoke as all materials eventually caught fire. The culprit was
not so much the filament material than the poor quality of vacuum in early lamp prototypes.
Emergence and development of practical incandescent lamps
The development of incandescent filament lamps owes a lot to that of vacuum
pumps. In 1838 it was discovered that carbon brought to incandescent does
not consume in a air-free environment. From this knowledge the enclosed arc
lamp was born in 1893 (Jandus and Mark) and had a lifetime of 150 hours, or
three to five times that of lamps burning in free air.
Although it was known that platinum wires could be brought to
incandescence in open air for a long time (de la Rue, 1802), the need for
lamps with higher filament temperatures was felt. Carbon rods were studied
and used by J.W. Starr and M.J. Roberts between 1840 and 1854. The former
made in 1845 a lamp partially evacuated with a mercury column from
Torricelli’s barometer. Lodyguine, a Russian scientist, circumvented in 1856
the problem of poor vacuum by using an atmosphere of nitrogen instead. Two
hundred of his carbon rod lamps were successfully used for lighting the
harbor of St Petersburg. These first lamps, although successful in their own
right, did not show a good lifetime due to the presence of residual impurity
gases either in nitrogen or in vacuum.
Figure 3: Goebel’s lamps.
(ca. 1854, [1])
3
Two major breakthroughs speeded up the development toward a commercially viable lamp. First, in 1865
Sprengel invented the mercury-drop vacuum pump, which was much better than von Guericke’s pump
developed around two hundred years before. This new device could evacuate a vessel down to at least a ten
thousandth of the atmospheric pressure (10 Pa), a factor hundred lower that previously achieved. L. Boem
then improved this pump in 1878, and reached a millionth of atmospheric pressure (10 mPa).
However, no matter how good lamps were pumped down, their lifetime was still too short (several
hours at best). The reason for this was discovered in 1879 by Francis Jehl and Thomas Edison (USA), who
found that gases occluded in lamp materials are released in vacuum over time. They then patented an
effective outgassing method, which consisted of heating the lamp during the pump-down process. In
February of this same year, Joseph Swan demonstrated a working incandescent graphite rod lamp before the
Royal Institution in Newcastle, England. This was eight months before Edison made his successful lowresistance
carbon filament lamp.
Historically, Swan was the first to achieve a
working carbon incandescent lamp. However, the
lamp lifetime was reportedly too short to be
commercially viable, which was not the case of
Edison’s lamp. Edison primarily used a U-shaped
carbonized cotton thread for the filament, later
replaced by a carbonized bamboo fiber which
boasted a luminous efficacy of 2 lm/W (ten times
lower that today’s standard filament lamps) and a
lifetime of 45 hours.
By the end of the 1870’s, the principles for
making a good incandescent lamp were
established, and it was then agreed that a lowresistance
filament was needed for its use in
parallel circuits. This set the requirements for
thinner filament, which are prone to burn out
quickly in poor vacuum. A better lamp thus called
for stringent improvements of the making procedures and the quality of the materials. Then from 1880 to
1883 many inventors worked at improving the quality of the carbon filament. Swan came up with a novel
process that consisted of squirting reconstituted cotton into threads, which were carbonized into very fine
carbon filaments of constant diameters. In 1894, A. Malignani introduced the use of red phosphorus as a
chemical getter, which maintains an excellent level of vacuum in the bulb throughout the lamp life.
The search for higher luminous efficacies and color temperatures pushed the research toward higher
filament temperature. Besides a shortening of their lifetime, this led to the severe blackening of lamp bulbs
as carbon has a high vapor pressure. Then, more refractory filament materials were needed in order to reach
more than 1200ºC. In 1893, Lodyguine investigated several metals, which included tungsten, while four
years later Carl Auer von Welsbach succeeded at making an osmium filament lamp that was put on market
in 1902. Followed in 1905, Dr Hans Kuzel made the
first (brittle) tungsten filaments, which were used in
new lamps marketed the year after. This novel source
pushed the lifetime up to 1000 hours and had an
efficacy of 8 lm/W (two times that of carbon filament
lamps), which eventually put an end to the osmium
lamp of Auer von Welsbach. In 1907, these lamps
were also made to operate on 110V mains and were
available up to the 500W size.
The next major breakthroughs happened from the
work of William Coolidge (General Electric, USA),
who in 1910 succeeded at making ductile tungsten filaments (as opposed to those made until then). Because
of its higher mechanical strength, this filament could be operated at a higher temperature, thus boosting the
Figure 5: Coiled-coil (top, 1933) and
simple coil (bottom, 1913) filaments. ([1])
Figure 4: Carbon filament lamps made by AEG from
Edison’s patents. (ca. 1900, [1])
4
lamp efficacy to 10 lm/W. Two years later, Langmuir discovered the benefits of coiled tungsten filaments
operating in inert atmospheres (nitrogen, then argon-nitrogen mixture). The winding permitted a reduction
of the filament thermal losses, while the surrounding gas lowered its evaporation rate. Both combined, this
gave a lamp efficacy of 12 lm/W (first marketed by GE in 1913 in 500, 700 and 1000W sizes) and spelled
the end of all carbon and other straight filament lamps.
From this point on, the development of incandescent sources slowed down. In 1933, the first coiled-coil
tungsten filament lamp was made available for general lighting, although it was already in use since 1913
for projection purposes. The following years saw the introduction of krypton and xenon-filled lamps having
higher filament temperatures owing to reduced evaporation rates. The impact of these later lamps was
limited because the use of heavier gases did no lead to an efficacy increase higher than ten percents.
The last major advance in this domain happened at the
end of the 1950’s with the making by Zuber and Mosby
(GE) of the first viable tungsten lamp having a filling of
halogens. The presence of this class of elements allows a
chemical cycle to return evaporated tungsten atoms back to
its source. This permitted the use of ultra-compact packages
with 100% lumen maintenance throughout lamp life (no
bulb blackening). Also, its efficacy was raised to 20 lm/W
an later to 26 lm/W, thus making the most efficient
incandescent lamp yet.
These sources were first marketed in 1962 and triggered
an explosive development of compact lamps for general,
studio, automotive, flood lighting and movie projection. In
the 1980’s the first low voltage capsule lamps integrated or
not in compact reflectors were put on the market, while infrared-reflecting coatings were tried at the
beginning of the 1990’s in an attempt to further decrease the thermal losses of the filaments.
Their pathetic efficacies make incandescent lamps more suitable for heating purpose than lighting.
However, low production costs and simplicity of use (no current-limiting ballast required) ensures them
several decades of strong use at home and for commercial lighting. If the future see the development of
stable up-converting phosphors transforming infrared into visible light, or that of proper tungsten optical
band-gap crystals, then incandescent sources will be able to compete with vapor discharge lamps.
The rise of electric discharge and arc lighting
The only practical light sources worked out until 1860 where of incandescent nature. Even the brilliant
carbon arc emits its light mainly from the white-hot anode; the contribution from the arc being relatively
negligible. This year, on September 3rd, the Hungerford suspension bridge
in London was lighted with the first mercury arc lamps ever made. This
invention from J.T. Way was a carbon arc enclosed in an atmosphere of
air and mercury vapor. This was the first time the arc itself was the source
of light.
Mercury in light sources poses today an environmental threat and
work are carried out to suppress it. By then it made a lot of sense to use it,
as this is the only metal with an appreciable vapor pressure at room
temperature and can emit a large proportion of visible light when
energized in electrical discharges. This known fact led to the invention of
the low-pressure mercury lamp by Peter Cooper-Hewitt (USA) in 1901,
followed by a quartz atmospheric-pressure version by R. Küch and T.
Retschinsky (Germany) in 1906 (marketed in 1908 by Westinghouse).
These lamps performed stunningly well by 1900 standards, they had
efficiencies many times that of carbon filament lamps. The reason for this
resides in the light emission mechanisms that are different in these two
Figure 7: J.T. Way’s mercury
arc lamp. (1860)
Figure 6: Original 500W tungsten-halogen
incandescent lamp. (GE, 1959, [2])
5
kinds of lamps. Incandescence arises from high thermal energy (i.e. lattice vibrations in the filament
material) that allows the emission of visible light. Consequently, a large portion of the emitted radiation is
in the infrared (95% of input energy in standard filament lamps). As opposed to this, an electric discharges
and arcs emit their light upon excitation and relaxation of gas or vapor atoms and molecules from electron
impacts. Thus more input energy can be radiated into useful visible light, leading to much higher
efficiencies (e.g. 35% visible light for low-pressure sodium vapor). However, the difference between the
two kinds of light sources lies also in their emission spectra. If incandescent lamps give excellent light color
renditions, electric discharge lamps at this time did not.
It was recognized that Cooper-Hewitt and Küch-
Retschinsky lamps emitted a bluish light deficient in
red, thus having poor color rendering properties. This
limited their use to streets, warehouses and industries.
This particular problem was addressed with seriesconnected
filament lamps that provided the additional
red light and stabilized the electrical discharge.
The extensive use of both types of mercury lamps
started when proper electrodes were developed. Until
the 1930’s, the original lamps had electrodes made of
mercury pools, which waste a lot of electrical energy
for the supply of electrons to the discharge.
High-pressure mercury lamps – the forerunners
The lamp from Küch and Retschinsky had a limited success due to many unsolved problems, like proper
electrodes, no tight quartz-to-metal seals and strong UV emissions leading to skin injuries. In the beginning
of the 1930’s, many lighting companies worked to address these problems and aimed at presenting an
atmospheric-pressure mercury lamp on the market.
In 1932, General Electric Company
of England (GEC) was the first to present
such a lamp under the tradename “Osira”.
Because no satisfactory sealing technique
between quartz and tungsten was found,
this lamp used a discharge tube made of
aluminosilicate hard glass. The relatively
low softening temperature of this material
limited the power loading of the electric
arc to 10-100 W/cm and restricted its use to the vertical position. This
later problem was eventually solved by the use of an electromagnet
that kept the arc straight when the lamp was horizontally operated.
The efficacy of such lamp was 30 to 40 lm/W, with a lifetime of a
couple of thousands hours. The low power loading of the arc and the
subsequent electrode power losses did not allow the making of
efficient low-power mercury lamps. Only the 400 and 250W sizes
were made available in this configuration. Also worth of interest,
these original lamps did not integrate any starting aid, like an auxiliary
probe. Thus GEC fitted each luminary with a small Tesla coil in order
to ignite the lamp. This was certainly the first time that an igniter was
used.
By the end of the 1930’s, Willem Elenbaas (Philips, the
Netherlands) theoretically predicted a rise of mercury lamp efficacy
with the increase of the arc power loading. This was effectively
verified after the invention of quartz-to-tungsten graded seals in 1935
Figure 10: The first high-pressure
mercury lamp. (Philips HP300,
1936, [5])
Figure 8: Küch and Retschinsky’s quartz
mercury arc lamp. (1906, [3])
Figure 9: The “Osira” mercury lamp. (GEC, 1932, [4])
6
(Cornelis Bol – Philips). The next year, Philips was then able to market the first low-power high-pressure
(20 atmosphere) lamp, the HP300 (75W). This was followed by a breakthrough source: the water-cooled
SP500W working at 80 atmospheres (Philips). Not only these lamps had a better efficacy (40 and 60 lm/W
respectively), they also showed improved color rendering properties owing to the higher operating pressure.
The SP500W lamp was primarily designed and
used for film projection and floodlighting
applications, while the HP300 remained favored for
street and industrial lighting due to its still
insufficient emission of red light. This problem of
color rendering pushed the research toward colorimproved
lamps that used an integrated incandescent
filament (acting also as a ballast – 1941) and/or a
phosphor coating on the inner surface of the outer
bulb to transform useless ultra violets into red light,
thus filling the gap in the mercury spectrum.
In 1934, cadmium sulfide was found to be a suitable
fluorescent material, although it provided only a mild color
correction. The introduction of the color-corrected mercury
lamp was made possible with the elaboration of manganeseactivated
magnesium germanate and fluorogermanate in
1950, which improved greatly the color rendering index and
had a beneficial effect of the lamp efficacy. Three years
later, tin-activated orthophosphate was introduced, and in an
attempt to have proportionally more red emission, “deluxe”
lamps with a rosy glaze on the outer bulb were marketed for
a short while by a number of manufacturers (1956). Then in
1967, the hugely successful europium-activated vanadate
and phospho-vanadate phosphors inherited
from color TV technology were introduced
and are still in use today. These modern colorimproved
mercury lamps have a color
rendering index (CRI) of 65 against 15 for
clear lamps and a luminous efficacy of 60
lm/W.
The present design results from a large
number of improvements in the lamp structure
that occurred in the 1950’s and 1960’s.
Among them are new kinds of quartz-to-metal
seals using 20 micron-thick molybdenum foils
pressed in quartz. Also, the changeover from
thorium to alkali oxide electrodes (Osram,
Germany) permitted a better lumen
maintenance throughout lamp life.
The last major innovation concerning
these lamps occurred in 1998 with the
invention of UHP (Ultra High
Figure 11: One of the first fluorescent highpressure
mercury lamps. (Philips, 1950, [6])
Figure 13: Various modern high-pressure mercury
lamps.
Figure 12: Super-high pressure mercury
lamps, then and now.
7
Performance/Pressure) lamps by Hanns Fischer (Philips) for LCD projection purposes. These new sources
operate with an internal pressure of about 200 atmospheres, thus leading to a strong continuum in the
emission spectrum and a high arc power loading. These make this kind of lamp efficient (60 lm/W) and
optically small (0.7 mm arc gap), thus allowing for an excellent optical control.
Standard high-pressure mercury lamps (not UHP) are today on the brink of extinction because of the
environmental threat posed by mercury, and their relatively poor performances compared to metal halide
and high-pressure sodium sources.
Metal halide lamps – the legacy of mercury sources
It was recognized since the earliest days of mercury lamps that the lack of red light in their emission
spectrum impeded heavily on their widespread use. In 1906, Guercke already suggested to add some redemitting
metals to the lamp of Küch and Retschinsky in order to improve its color properties. M. Wolke
followed this procedure in 1912 and used cadmium and zinc. This turned out to be unsuccessful due to a
low lamp cold-spot temperature (600ºC), which led to an insufficient zinc and cadmium vapor pressures.
Also, these metals readily attacked the quartz envelope, thus rendering the lamp useless after a couple of
tens of hours of operation.
The development of suitable
fluorescent materials and ballasting
filaments dampened the need for colorimproved
mercury arcs. However, studies
were still going on possible additives for
the mercury lamp in order to increase its
luminous efficacy, regardless of color
properties. In 1941, Schnetzler made a
mercury-thallium lamp having an
efficiency of 70 lm/W, almost twice as
high as its mercury counterpart. The
desired thallium vapor pressure was
reached by operating the arc tube at thrice its normal power
loading, with the consequence we can imagine on the life
expectancy.
In the next decade, studies turned toward metal-halogen
compounds that have higher vapor pressures than metals at a
given temperature. Gilbert Reiling (GE) patented the first metal
halide lamp in 1961, which was intended to replace highpressure
mercury lamps in their sockets. It had a filling
primarily of mercury, thallium and sodium iodide that showed
a sizeable increase of lamp efficacy (up to 100 lm/W) and color
properties, and made it more suitable for commercial, street
and industrial lighting. Eventually GE marketed this lamp in
1964 with additives of sodium and scandium iodides instead.
Most major manufacturers followed shortly thereafter, with
varied compositions in order to meet different lighting needs
and to circumvent competitors’ patents. Today the most
popular additives are sodium-scandium iodides, lithiumsodium-
thallium-indium halides and several mixtures of rareearth
halides.
The sixties and seventies witnessed a furious development of metal-halide lamps in different geometries
from tubular to reflector, and in power range between 175W and 5000W in order to meet the soaring
demands in the many applications it found. One of the last strongholds this kind of source did not invade
was at home. At the end of the 1970’s GE, Sylvania (USA) and Philips designed prototypes of self-ballasted
Figure 14: Reiling’s metal halide lamp. (GE, 1961, [7])
Figure 15: Self-ballasted metal halide
lamp. (ca. 1980, GE MaxiLight 55W)
8
metal-halide lamps intended to replace standard filament lamps for domestic applications. This was
ultimately proven unsuccessful due to some lethal drawbacks such as the lack of hot re-strike capabilities
and the prohibitive cost of the lamps.
Two major breakthroughs followed at the beginning of the 1980’s. In 1981, Thorn Lighting (England)
presented the first metal halide lamp with a sintered alumina ceramic discharge tube, which resulted from
ten years of research and development. Unfortunately, this revolutionary source did not reach the market
due to a lamp voltage/current characteristic that
did not match any available ballast. Around the
same year, and with more success, Osram
introduced its compact double-ended HQI-TS
lamps that found an application in shop-window
and commercial lighting.
In 1991, Osram, Philips, Valeo and many other
car equipment manufacturers engaged themselves
in the ‘vedilis’ project, which led to the xenonmetal
halide lamps (D1 and D2) for automotive
headlights. Philips then revived metal halide lamps
with ceramic discharge tubes in 1995, when it
launched its range of CDM lamps. Osram and GE
soon followed. These lamps present today an
alternative to high-pressure sodium sources for
downtown street lighting. The use of this particular design allows for a better lamp-to-lamp color matching,
higher efficacies and better color rendering. Even more so, the bluish light of metal halide performs better
than the orange hue of high-pressure sodium when scotopic vision prevails in low illumination levels at
night.
Low-pressure mercury fluorescent lamps – toward domestic applications
The origin of fluorescent tubes goes back to the invention in 1901 of the low-pressure mercury lamp by
Cooper-Hewitt. For the same reasons as its high-pressure counterpart, its use was restricted to places where
color rendering was not an issue. Right from the start, Cooper-Hewitt worked to improve his lamp by
applying some fluorescent dyes (primarily Rhodamine B) on the bulb surface and later on luminary
reflectors in order to compensate for the lack of red emission. The idea of using fluorescence to convert
invisible light into useful radiation was not new, and already in
1859 E. Becquerel tried to use Geissler tubes filled with fluorescent
materials in order to get a practical light source. His trials were not
successful as the efficacy was too low. Later in 1896, one year after
the discovery of X-rays by W. Röntgen, T. Edison made a X-ray
lamp internally coated with calcium tungstate which radiated a
bluish white light. This source was three times as efficient as
carbon filament lamps, and had X-rays not caused severe injuries,
this lamp would have certainly been the first commercial
fluorescent source.
Back to the twentieth century, it was discovered in 1920 that an
electrical discharge in a proper mixture of argon and mercury at
low pressure could radiate efficiently (60% of power input)
ultraviolet light at 253.7nm and 184.9 nm. Six years later, Meyer,
Spanner and Germer from Osram (Germany) published a landmark
report where they described a low-pressure mercury vapor lamp
provided with externally-heated oxide-coated electrodes, and an internally phosphor-coated bulb to convert
UV radiation into visible light. This document set what would become the first successful fluorescent tubes.
However, its marketing had to wait for the development of efficient electron-emitting electrodes by M.
Figure 17: Cooper-Hewitt tube
connected in series with carbon
filament lamps, which act as a
ballast. (ca. 1910, [8])
Figure 16: Various compact metal halide lamps.
9
Pirani and A. Rüttenauer (Osram) in 1932, and the elaboration of the calcium tungstate – zinc silicate
phosphor. Then in September of 1935, the first tubular fluorescent lamp was demonstrated before the
Illuminating Engineering Society in Cincinnati, North America. This was presumably from General
Electric, who had taken over the patent of André Claude on a similar fluorescent tube in 1932. Osram
followed in 1936, and displayed its ‘L’ lamp at the World Exhibition held in Paris. Between 1936 and 1938,
most major lamp manufacturers made fluorescent tubes available both in Europe and in the US for general
lighting applications. These lamps had a tube diameter of 38mm, an efficiency of about 30 lm/W and a
moderate color-rendering index, yet good enough for its use at home.
Figure 18: Philips TL100 and ballasting device from 1939. ([5])
In 1942, A.H. McKeag from GEC (England) made a giant leap with the discovery of calcium and
strontium-activated halophosphates. Lamps using this phosphor
formulation were introduced in 1946 and had twice the efficacy of
former tubes, while the color rendering was much improved.
Philips made the next step with the introduction in 1973 of the
three-band phosphors. This boosted the efficacy up to 90 lm/W
with excellent color rendition (IRC 80-90). This new formulation
also allowed the increase of the lamp wall power loading and led
to the reduction of the tube diameter from 38mm (T12) to
26mm (T8), and then to 16mm (T5) at the beginning of the 1980s.
A decade later, Osram shrunk things further and put a 7mmdiameter
(T2) fluorescent tube on the market (Lumilux-FM).
The reduction of lamp size permitted the design of compact
fluorescent lamps with integrated ballast. The first of this kind was
presented by Philips at a world technical conference held in
Eindhoven in 1976. In 1980, this company introduced successfully
its SL*18, followed by an electronic version in 1982. Competitors
were quick to catch up and by the end of the 1980’s compact
fluorescent lamps were widely available at a reduced cost and package size. The success of these lamps was
partly due to the energy crisis that raised the cost of electric
consumption, thus calling for more efficient and cost-effective light
sources.
At last and not least, from the eighties until the mid-nineties
several lamp makers introduced electrodeless versions of fluorescent
lamps. In these sources the discharge originates from an
electromagnetic field generated by an induction coil antenna. The
suppression of the electrodes increases the lamp lifetime up to sixty to
a hundred thousands of hours.
Fluorescent lamps were the first and only discharge lamps to reach
the level of domestic lighting. Today, they provide a wide range of
color temperature with excellent color rendition and high efficacies.
This explains why they account for seventy percent of all lamps used
in commercial illuminations. Development still continues today, and
priorities are set to size and efficiency. To this respect, the use of
Figure 19: First successful compact
fluorescent lamp. (Philips, 1976)
Figure 20: Electrodeless mercury
fluorescent lamp. (Philips QL55)
10
surface-mounted electronic components permitted the making of smaller CFL lamps to fit in low-power
luminaries, therefore claiming more ground to its incandescent counterpart.
Low-pressure sodium lamps – reaching summits in efficacy
Extensive experiments with electrical discharges in alkali vapors could have started only in 1920 when A.H.
Compton formulated a borate glass resistant to sodium. Alkalis, being strong reducers, require special
glasses as normal materials like soda-lime silicates are readily attacked and lead to the formation of a brown
light-absorbing film. Two years later, in 1922, M. Pirani and E. Lax from Osram experimented sodium
discharges for lighting applications. The following year, Compton and C.C. van Voorhis in the USA
attained an efficacy of 340 lm/W with a lamp externally heated by an oven. Naturally, the calculation of the
efficacy did not take into account the energy provided to keep the lamp at its optimum working temperature
of 260°C.
Then, in 1931, both Philips and Osram made the first viable
low-pressure sodium lamps, and the following year a stretch of
road between Beek and Geleen, in the Netherlands was lighted
with Philips lamps. These sources were DC-operated via an
externally heated cathode and had an efficacy of about 50 lm/W. A
Dewar flask surrounded the discharge tube in order to limit the
thermal losses. In 1933 followed the AC-driven positive column
type of lamp, which had a higher efficacy partly due to a more
favorable current density in the discharge.
From 1933 until 1958, lamps were composed of a separate
discharge tube and a double-walled vacuum flask. In 1958, Philips
marketed an integral lamp, which included the discharge tube
within an evacuated bulb thus preventing the former from getting
dirty, as it was the case in the previous design. Subsequent work
was done on increasing the lamp efficacy by improving its thermal
insulation. A first solution consisted of enclosing the discharge
tube in several infrared-absorbing glass sleeves. Then infrared
mirrors made of gold or bismuth
thin films were employed. Philips
made a leap forward in 1965 with
the introduction of the tin oxide
semiconductor mirror, and later the
better tin-doped indium oxide film.
These materials exhibit a strong
infrared reflectivity while being
highly transparent to sodium light.
This led in 1983 to a lamp reaching
the symbolic barrier of 200 lm/W
(SOX-E, by Philips), which is the
highest efficacy reached yet.
The reason why low-pressure sodium is so efficient at producing visible light is that this element, under
the right conditions, radiates an almost-monochromatic yellow light almost coinciding with the peak
sensitivity of the human eye in photopic vision. Also, this yellow light emission corresponds to transitions
from the two lowest (resonant) energy levels of sodium, thus allowing an efficient transfer of energy from
the electric discharge to the excitation of sodium atoms.
In the 1980s, several low-power lamps were experimented for replacing filament lamps in security
lighting. Technically these sources were successful but their prohibitive cost and the need for specific
Figure 21: The first low-pressure
sodium discharge lamp. (Philips,
1932, [9])
Figure 22: Sodium lamp with bamboo-shaped discharge tube and
detachable Dewar outer jacket. (Philips SO/H60W, 1955)
11
ballasts prevented their widespread use. Interestingly, Philips designed a LPS lamp that had electrical
characteristics closely matching that of existing fluorescent tubes, so the ballasting equipment was already
standard.
Today, low-pressure sodium lamps remain unchallenged in terms of luminous efficacy. Its bi-chromatic
orange spectrum is the key to its efficiency, but is also
the limitation factor that restrains its use for street and
industrial lighting. In return, its light leads to excellent
seeing contrasts, particularly in foggy weather. Further
developments of these sources concern its highfrequency
operation and improvement of thermal
insulation, which will certainly bring the efficacy up
to 230 lm/W in a more or less distant future. Also
worth of interest is the development of electrodeless
versions that obviate the need for life-limiting parts
such as the electrodes. These sources are however not
likely to reach the market due to difficulties in the
making of a proper discharge vessel.
High-pressure sodium lamps – a compromise between color and efficacy
It was known that increasing the pressure of a sodium discharge would lead to a lower efficacy, but also to a
broader and richer spectrum having better color-rendering properties. The borate glass originally developed
by Compton and the other materials used in low-pressure sodium lamps are not suitable for high-pressure
operation. As the power loading and the temperature of the discharge increase, the reactivity of sodium
toward the wall increases and lamps
degrades themselves within minutes of
operation. Then, the development of the
high-pressure sodium (HPS) lamp had to
wait for the work of Cahoon and
Christensen in 1955-57, and that in 1955
of R.L. Coble on tubes made of sintered
translucent alumina. This material was
found to be resistant and impermeable to alkalis, thus making it suitable for high-pressure sodium lamps.
During the following years, systematic studies were carried out on high-pressure alkali discharges.
Among them, cesium looked promising due to its relatively white spectrum. However, the final choice was
sodium because of its good compromise between
efficacy and color rendering. The development of
suitable sealing and manufacturing techniques
allowed William Louden and Kurt Schmidt (GE)
to make the first practicable high-pressure sodium
lamps in 1964. The next year, GE launched an
industrial full-scale production and a 400W lamp
was made available in 1966 under the ‘Lucalox’
brand name. A 250W version followed three
years later. Their efficacies ranged between 90
and 100 lm/W with a life expectancy of 6000
hours. Refinements in the 1980’s extended the
lifetime to 24,000 hours and the efficacy between
100 and 140 lm/W with a color-rendering index
of 20-25.
The design of this lamp was radically
different than that of metal halide and the mercury
Figure 23: Two special low-pressure sodium
lamps for security lighting. (1980’s)
Figure 25: Early range of sodium lamps from GE.
(1966, [11])
Figure 24: The first high-pressure alkali vapor ceramic
discharge tube. (GE, 1961, [10])
12
lamps. It also called for different types of ballasts. While metal halide and mercury sources were and still
are powered in the USA with step-up leakage transformers, high-pressure sodium lamps required a choke
and an external igniter. Then followed several versions of lamps with built-in internal switches that use the
inductance of the choke to kick-start the discharge tube.
Most of these sources have a filling of mercury, xenon and sodium. The role of xenon is to allow the
lamp to start, while mercury sets the electric field in the lamp discharge (positive column) and does not
contribute to the emission spectrum. Without it, the lamp voltage drop would be too low and the current too
high, thus requiring an inefficient and bulky ballast and impairing the luminous efficacy. The environmental
problems caused by mercury forces its suppression, and mercury-free HPS lamps were made available by
mid 1990’s. These lamps have a higher xenon pressure and some starting aid like sintered metal strips on
the discharge tube surface (Philips).
The 1980’s saw also the development of the so-called white HPS lamps by Thorn, Philips and Iwasaki
(Japan), which provide an incandescent-like color at four times the efficacy of tungsten filament lamps.
These sources are still popular today even with the advent of ceramic metal halide lamps. The advantages of
white HPS lies in the large portion of red light in its emission spectrum, leading to a color temperature as
low as 2500K. Metal halide lamps cannot reach such war white tone. Also worth of notice is a lamp
developed in the mid-1990s by Osram (DSX-T), which has its color temperature that can be changed from
2700K (standard tungsten white) to 2900K (tungsten halogen white) by a flick of a switch.
Bright perspectives
The field of lighting had many changes since the revolution in lifestyle and lightstyle Davys’s discoveries
induced! So affected has been and still is the field of lamp manufacturing. The eighteenth century witnessed
the slow emergence of precursors that led to the exponential development of myriads of sources in the next
hundred years. By the dawn of the twentieth century, thousands of lamp makers were struggling on a
boiling market, and to say the truth, it was not far from easy to jump in this business since techniques and
physics involved at this time were not as developed as today. A century later, only three major (general)
manufacturers have survived: Philips, Osram and GE, who count more than 3500 references in their product
catalogs. A couple of hundred of medium-sized, minor or specialized manufacturers surround them. They
are now facing new challenges that will change our lifestyle and lightstyle through the 21st century: the
development and extensive use of white LEDs, and the abandon of harmful materials in all vapor discharge
lamps while still pushing upward their luminous efficacies and color rendering properties.
References
More technical and historical details are available at: http://www.geocities.com/mfgendre
[1] F.J.M. Bothe, AEG-Telefunken Ontladingen/Schakels, 57 p., June 1979.
[2] “Lighting progress in 1959”, Illuminating Engineering, pp.140, March 1960.
[3] R. Küch and T. Retschinsky, “Photometrische und spektralphotometrische messungen am
quecksilberbogen bei hohem dampfdruck”, Annalen der Physik, vol. 20, pp. 563-583, June 1906.
[4] C.C. Paterson, “Luminous discharge tube lighting”, The journal of good lighting, pp.308-318,
December 1932.
[5] P.J. Oranje, Gasontladingslampen, Uitgave Meulenhoff & Co., Amsterdam, 288p., 1942.
[6] J.L. Ouweltjes, W. Elenbaas and K.R. Labberté, “A new high-pressure mercury lamp with fluorescent
bulb”, Philips Technical Review, no. 5, pp. 109-144, November 1951.
[7] G.H. Reiling, “Metallic halide discharge lamps”, US patent #3,234,421, January 23rd, 1961.
[8] G.W. Stoer, History of lights and lighting, Philips Lighting B.V., the Netherlands, 46 p., 1988.
[9] “Fifty years of low-pressure sodium lighting”, Philips Lighting News, no. 8, 1982.
[10] K. Schmidt, “Metal vapor lamps”, US patent #2,971,110, February 7th, 1961.
[11] W.C. Louden and W.C. Matz, “High-intensity sodium lamp design data for various sizes”, Illuminating
Engineering, pp. 560-561, September 1966.

Windrush
Square
21
7
Brixton
Railway
Station
Brixton
Village
Brixton Road
Acre Lane
Brixton Hill
Effra Road
Rushcroft Rd
Saltoun Rd
Atlantic Rd
Electric Av
Porden Road
Electric La
1 2
19
14
18
17
15
16
20
6
9
8
3
13
5
4
Coldharbour Lane
10 11
12
Brixton
Tube Station
BRIXTON
Start at Tate Library , built in 1892 in Victorian
Classical style. It was funded by Henry Tate of
Tate & Lyle, the sugar merchants.
Tate invented the sugar cube.
Find his bust in front of the Library.
By the library is the Sharpeville Monument .
It was built to commemorate black people killed on
21 March 1960 when police opened fire on a peaceful
protest in the South African township of Sharpeville.
Walk on into Windrush Square , created to celebrate
the 50th anniversary of the arrival of SS Windrush from
the Caribbean in 1948 with 492 West Indians on board.
Many of them settled in Brixton. On the south-east corner
of the square is the Maidenhair Tree , Gingko biloba,
one of the oldest tree species in the world. There is an
old-fashioned Bovril advertisement
painted on the side of a building to the east.
Look out for other signs like this.
There’s one in Electric Lane,
near Atlantic Avenue.
Cross Effra Road and turn right toward the junction and
the Budd Memorial . This was erected in 1825 by
Henry Budd in memory of his father Richard Budd, ‘a
respected parent’, who was born in Brixton in 1748.
The serpent eating its tail is
the symbol for eternal life.
Can you find it?
Walk through the gardens to
St. Matthew’s Church . Built in
1822, it was one of four ‘Waterloo’ churches built in South
London in the early 19th century. The road opposite,
Porden Road, is named after its architect, C.F. Porden.
Turn right down Brixton Hill passing The Fridge on
your left. One of London’s most famous music venues,
it was built in 1914 and used to be the Palladium Cinema.
Can you see the fridge doors that
decorate the front?
On the corner of Acre Lane is Lambeth Town Hall ,
built in 1908 with red brick and stone decoration.
9
8
7
6
5
4
3
2
1
The four figures around the tower
represent Justice, Science, Art, Literature.
Which one is Justice and
how can you tell?
Cross the road to Coldharbour Lane. The Ritzy Cinema
, opened in 1911 as the ‘Electric Pavilion Cinema’, is
the second oldest cinema in London.
Can you find the angels
holding up the letters E and P
for Electric Pavillion?
In front of the Ritzy is the London Plane
Tree , Acer Platanus x acerifolia,
ideal for London streets as it is not harmed by pollution.
Also here is the Foundation Stone of
the Old Brixton Theatre ,
bombed during World War II. It was
laid by the famous actor Henry Irving.
Can you find the
architect’s name?
You are now walking down Coldharbour Lane , once
a winding country lane connecting Brixton to Camberwell.
13
12
11
10
There’s a lot to see and do right
on your doorstep. One of the best
ways to explore is to take a
Lambeth Walk. This walk has been
put together by Lambeth Council
to help you discover more about
Brixton and the surrounding areas
of Herne Hill and Ruskin Park.
Brixton is right at the heart of Lambeth. Here, you’ll find
the market, the town hall, the Ritzy cinema and a huge
number of other things to see and do. As you walk, you’ll
pass through two of Lambeth’s most popular parks and
see some of the wildlife on offer.
The walk starts at the Brixton Tate Library and ends
further along Coldharbour Lane, just past Loughborough
Junction Station. To make the walk circular
you can head back along Coldharbour
Lane on foot (about 10 minutes) or take
the bus. The walk is expected to take
about 2 hours.
Brixton to
Ruskin Park
Walk
You’ll be able to learn about local history and
architecture, and some of the colourful
characters that have lived and died here. There’s
something to interest the whole family, and some very
particular activities and questions to keep the children
entertained. Some of the things you find out about can
be used to complete the quiz elsewhere in the pack.

Produced by the
Guardian in association
with decibel
ART IS
BLACK
CULTURALLY
DIVERSE ARTISTS
ON SHOW
02 ART IS BLACK
ALJIT BALROW IS THE FACE OF HAPPYclappy,
off-the-peg multiculturalism.
Literally. Her cute face modelling Indian
wedding jewellery and painted with the
British flag proves there IS some “Black
in the Union Jack” and embodies the
celebratory agenda of the Channel 4 Self
Portrait UK campaign. It’s always
captioned, “My parents see me as Indian,
but my friends see me as British. I see
myself as both British and Indian.” Very
melting pot.
But Balrow originally produced the
self-portrait as one in a series of shots,
the paint vanishing one colour per frame
to reveal the Indian face beneath,
representing a rejection of British
jingoistic flag-wavers alongside that
more defiantly celebratory vibe. Balrow
engages with her Sikh heritage
artistically because “it’s the same kind of
relationship you have with your artwork
as with your identity”.
But she distinguishes between a
useful internal dialogue and the banal
terms in which ethnic identity is framed
in the public domain. Since taking part in
a British Council sponsored tour of India
with a random bunch of other British
Asian artists, she’s no longer Asianartist-
for-hire because it eclipses her
specialism as a portraitist. She is now
teaming up with artists she met in India
in a joint exhibition but explains, “It’s not
Asian artists’ work, it’s artwork by artists
who happen to be Asian.”
Black and Asian artists working in
more abstract forms often bristle at the
association with identity politics. In 1989
Anish Kapoor refused to take part in The
Other Story, a landmark exhibition of
black and Asian artists at the Hayward
Gallery, reasoning, “I believe that being
an artist is more than being an Indian
artist. I feel supportive to that kind of
endeavour… it needs to happen once; I
hope that show is never necessary again.”
Ten years later, public galleries still
seem out of step with such artists. Art
historian Niru Ratnam panned an
exhibition showcasing young Asian
artists in 1999, saying “We simply do not
need insulting patronising shows like
zerozerozero ever again.”
Alex Proud, a private gallery owner
specialising in music photography, finds
the idea of defining work through the
ethnicity of the artist baffling. He says
diversity sells and black photographers
may be best positioned to capitalise
because, “skin colour stopped being a
barrier in photography a long time ago”.
A recent exhibition of Bob Marley pictures
by black photographer Dennis Morris was
a commercial success and Proud is now
talking to KFC about sponsoring an
exhibition of soul photographs.
Sara Wajidis project director
(development) of SALIDAA, South Asian
Diasporic Literature and Arts Archive
(www.salidaa.org.uk). She curated Our
Man in India: Cecil Beaton’s Propaganda
Photographs 1944, at The National
Archives, Kew, to Mar 13
B
What’s in a
name?
Above, Self portrait
with jewellery-feet;
Red Nude [also on
cover]. Right, Sydney.
All by Baljit Balrow
Baljit Balrow; Graham Turner; Aquarius
Is racial and cultural identity
important to visual artists?
Or are we just one happy
multicultural family now?
Is this the job of the commercial
gallery? Mr Aftab cites the film and music
industries where he believes there is a
more progressive attitude towards
encouraging young black and Asian
people. Public bodies are all very well, but
it is the big commercial galleries with the
cash. If they want to be seen as a globalised
community perhaps they should be
proactive in providing opportunities for
those who feel alienated from entering it.
Jessica Lack
ART IS BLACK 03
Steve McQueen. Top,
Isaac Julien’s film
Looking for Langston
Spend, spend,
spend
At a time when famousname
artists get big bucks,
does race still affect your
selling power?
IT WAS A VERY DIFFERENT LONDON
when the GLC Leader Ken Livingston
was mocked for spending public money
on tabloid-unfriendly groups such as
black and Asian artists. It was an act
that caused derision from Middle
Englanders and added to his
description as a loony lefty.
Today the idea of describing artists like
Anish Kapoor, Chris Ofili, and Steve
McQueen as part of a marginalised
artistic community would seem
laughable. They have not only received
the highest art accolades Britain has to
offer, but their paintings, sculptures and
films fetch the kind of prices most mere
mortals could retire on.
Has their race effected their selling
power? Niru Ratnam, co-director of the
Store Gallery in Hoxton doesn’t think so
and is mildly amused to think of
exhibitions by artists such as Lubaina
Himid or David Adjaye, as needing the
support of a decibel initiative.
“At the beginning of the 1990s it did
feel like the only artist of colour who had
gained public recognition was Anish
Kapoor, but things have changed
dramatically since then. There is a kind of
multicultural romanticism in the London
art world now. Gallery owners don’t have
a racial agenda to selling art. There are a
small few who choose to show only
works with a post-colonial slant, but
essentially dealers are interested in the
international appeal of their artists. In a
strange way”, says Ratnam,“you could
argue the market has become an
enabler of globalised peace in the art
world. It may be a cut-throat profession
but race doesn’t come into it.”
Film and art critic Kaleem Aftab is less
sure, “IThe gatekeepers are still white,
and although you can mention artists like
Kapoor, Isaac Julien and Runa Islam, I
still think there’s a kind of tokenism to the
way these artists are seen. You can argue
it’s a class thing, but that’s just sidestepping
the issue. Dealers might be
keen to attract black and Asian artists but
I don’t see them going into schools in the
East End or setting up scholarships.”
Is there racism in the visual arts? Join the debate, at
www.spiked-online.com/artsandracism/’
BCA Gallery
33 Castle Lane, Bedford (01234 273580)
www.bedfordcreativearts.org
Window on the World: Nilu Izadi
A solo exhibition of contemporary pinhole
and camera obscura photography by Nilu
Izadi, London-based photographer of
Iranian origin.
Tues-Sat 11am-5pm, ends Apr 17, free
Bonnington Gallery
Dryden Street, Nottingham (0115 848
6131) www.future-factory.com
Performance People: Harjeet Kaur
This work is preoccupied with action and
duration, which enthralls and draws the
audience in closer.
Mon-Thur 10am-5pm, Fri 10am-4pm, Sat
1pm-5pm, Apr 5 to May 14, free
Central Art Gallery
Old Street, Ashton-Under-Lyne, Greater
Manchester (0161-342 2650)
www.tameside.gov.uk
Parampara Portraits: J Chuhan
New perceptions of the British South
Asian experience through a series of
portraits of British South Asians in the
public eye.
Tues, Wed, Fri 10am-5pm, Thu 1pm-
7.30pm, Sat 9am-4pm, ends today, free
The City Gallery
90 Granby Street, Leicester LE1 (0116 254
0595)
Roshini Kempadoo: Works 1990-2004
Mapping colonial history, stories and
locations, Roshini Kempadoo uses new
technologies to explore connections
between past and present. Includes
Ghosting, commissioned to celebrate the
new Peepul Centre.
Tue-Fri 11am-6pm, Sat 10am-5pm ends
Apr 3, free
Crescent Arts, The Crescent,
Scarborough, North Yorks (01723 351461)
www.crescentarts.co.uk
Sculpture
Sculpture exhibition of local and national
artists from wire sculpture to 3D collage,
found objects and everything in between.
Ends today
Kids Art
An exhibition of diverse art produced by
children aged 5 to 15.
Mon-Sun 10am-1pm, 2pm-5pm, Mar 16
to Apr 24, free
Listings
All around England: where to see
culturally diverse artists on show
between now and July
04 ART IS BLACK
There is humour and pathos in the
paintings of Lubaina Himid, the
Tanzanian-born artist who, after
leaving the Royal College of Art.
formed the Black Women’s Art
Movement and became director of the
alternative art space, The Elbow
Room between 1986 and 1990. Himid
uses her pictures to introduce
dialogues about art and illusion,
guilefully rewriting history to include
depictions of black women and
lament the injustices of slavery and
oppression. Her new exhibition
features theatrically dressed cut-out
figures, withthe accompaniment of a
thumping operatic soundtrack that
challenges the relationship between
Europe’s colonial past and today’s
cultural politics. JL
The Hatton Gallery, Newcastle,
to Mar 13, free
FOCUS: Lubaina Himid
Cousins today, pictured at his home in Minorc apictured at
ART IS BLACK 05
exploring issues of forgotten histories,
race and identity.
Mon-Sat 10am-5pm, to Mar 13, free
John Hansard Gallery
University of Southampton, Highfield,
Southampton (023 8059 2158)
www.hansardgallery.org.uk
New British Painting: Part II
Exhibition of contemporary British
painters including Pearl Hsuing, Andrea
Medjesi-Jones, Miho Sato and others.
Tues-Fri 11am-5pm, Sat 11am-4pm,
ends Apr 7, free
Minories Art Gallery
74 High Street, Colchester, Essex (01206
577067) www.firstsite.uk.net
Gambiarra
A multi-ethnic, multimedia exhibition of
young Brazilian artists combining a
political voice with the methodology of
“gambiarra” or “making do”.
Mon-Sat 10am-5pm, Mar 5 to June 5, free
The New Art Gallery Walsall
Gallery Square, Walsall, West Midlands
(01922 654 400) www.artatwalsall.org.uk
Double Vision
Students curating their own exhibition,
drawing on the works from the Arts
Council Collection.
Strangers
Strangers gathers together works by 19
Cube
82 Wood Street, Liverpool, L1 (0161-237
5525) www.cube.org.uk
Asymmetrical Chamber: David Adjaye
Cube is committed to exploring
architecture in all its diversity and how it
interconnects with other visual arts
disciplines. Mon-Fri, 12noon-5.30pm, Sat
10am-5pm, to Mar 8, free
EMACA (East Midlands African
and Caribbean Arts)
Art Exchange, 39 Gregory Boulevard,
Nottingham (0115 924 4611)
Keisha Castello
Miniature painting and installation from
Jamaican artist. Mar 10 to Apr 2
My Other Life: Donovan Pennant
Installation and photography on the
artist’s reincarnation. Apr 9 to May 2
Urban Spirituals: Samson Kambalu
Ground-breaking retrospective of Malawiborn
artist, Samson Kambalu. Best
known for his Holy Ball exercises. July 5 to
Aug 24
Mon-Fri 10am-6pm, Sat 1pm-5pm, free
The Hatton Gallery
The Quadrangle, University of Newcastle,
Newcastle (0191-222 6059)
www.ncl.ac.uk/hatton
Naming the Money: Lubaina Himid
Installation of 100 life-sized cut-outs
Ian Teh spent the last four years
photographing the creation of the
largest dam in the world which will
force 2 million Chinese people to
leave their homes by the Yangtze
River. One of the most striking shots
depicts a barber cutting hair in his
shop, which is mid-demolition. Teh
deftly captures intimate domestic
details brutally exposed by
demolition. Technically perfect
compositions of natural beauty by the
award-winning press photographer
are mixed with blurry ones hinting at
a hovering bulldozer. SW
Photofusion, London SW9,
to Mar 27, free
FOCUS: Ian Teh
06 ART IS BLACK
modern and contemporary artists from
the Tate Collections whose practice
involves meeting or observing strangers.
Tues-Sat 10am-5pm, Sun 12noon-5pm,
ends Apr 18, free
Nottingham Castle
Off Maid Marian Way, Nottingham (0115
915 3700) www.nottinghamcity.gov.uk
Horace Ove
Landmark exhibition of 100 selected
images from the work of pioneering black
film-maker, documenting the emergent
black political scene in the 60s.
Mon-Sun 10am-5pm, May 1 to June 27,
free
Photofusion
17a Electric Lane, Brixton, London, SW9
(020-7738 5774) www.photofusion.org
The Vanishing: Ian Teh
A documentation of the recent
transformation to China’s Yangtze river
made by the construction of the giant
Three Gorges Dam. To Mar 27
Buena Memoria: Marcelo Brodsky
An impressive and moving memorial to
the thousands who went missing during
Argentina’s dictatorship. Apr 2 to May 15
Masquerade
Five contemporary women
photographers address the complexities
surrounding portraiture. May 28 to July 10
Tues, Thur, Fri 10am-5pm, Wed 10am-
8pm, Sat 11am-6pm, free
Photographers’ Gallery
Newport Street, WC2 (020-7831 1772)
Red-Colour News Soldier: Li Zhensheng
Photographs of the cultural revolution in
the city of Harbin, scene of mass witchhunts
by Red Guards.
Mao’s Photographers:
Hou Bo & Xu Xiaobing
In contrast to Li Zhengsheng’s frank and
courageous depiction of the real events of
the Cultural Revolution, this exhibition
focuses on how Mao Zedong recruited
photography for propagandist ends.
Mon-Sat 11am-6pm, Sun 12noon-6pm,
Apr 9 to May 30, free
PM Gallery & House
Walpole Park, Mattock Lane, Ealing, W5
(020-8567 1227)
www.ealing.gov.uk/pitshanger
Roshini Kempadoo
A retrospective exhibition of photographic
and web-based work including a new
commission referencing the gallery house
owned by John Soane.
Tues-Fri 1pm-5pm, Sat 11am-5pm, June
2004, free
The Potteries Museum & Art Gallery
Bethesda Street, Stoke on Trent, (01782
232323) www.stoke.gov.uk/museums
An artist who has been consistently
making engaging and thoughtprovoking
artworks for the last 14
years, it is only now that Roshini
Kempadoo is finally being
recognised for these investigative
pieces. Her new installation
Ghosting is unveiled this week and it
is a critical look at the history of the
slave trade using information
gleaned on the internet. Using the
arbitrary nature of cyberspace, she
creates links between countries and
people, exploring the impact
colonialisation has had on popular
culture, the way in which we
construct history, both personal and
national, and our aspirations.
She also has another show at PM
Gallery & House, Ealing, in June. JL
The City Gallery, Leicester,
to Apr 3, free
FOCUS: Roshini Kempadoo
Cousins today, pictured at his home in Minorc apictured at
ART IS BLACK 07
Diverse Designs
Twelve schools work with artists inspired by
the museum’s foreign collection.
Mon-Sat 10am-5pm, Sun 2pm-5pm, Apr
3-Apr 20, free
Q Arts
35/36 Queen Street, Derby (01332 295858)
www.g-arts.co.uk
Illustration of Life: Max Kandhola
A profound and moving photographic
narrative that challenges exiting ideas and
representation of death.
Mon-Sun 12noon-4pm, ends today, free
Royal Over-Seas League Arts
Over-Seas House, Park Place, St James’s
Street, London, SW1 www.rosl.org.uk
Hybrid: Chila Burman and Godfried
Donkor
New works by two highly acclaimed
artists working with pattern and detail.
Mon-Sat 10am-6pm, to Mar 5, free
The Showroom
44 Bonner Road, London, London E2 (020-
8983 4115) www.theshowroom.org
Subodh Gupta
Newly commissioned work by Delhibased
artist, elevating the status of found
objects from everyday items to artworks.
Mon-Sun 1pm to 6pm, Mar 31 to May 9, free
To Change an Opinion
One day conference on aesthetical forms
and political contents. Speakers include
Subodh Gupta and Michael Hirsch.
Apr 3, £20/ £10 (concessions). Tickets
from The Showroom, as above
Spacex Gallery
45 Preston Street, Exeter (01392 431 786)
www.spacex.co.uk
Homeland
A multi-site project — encompassing
shops, the cathedral, outdoor spaces and
the local newspaper — posing the
question “What is Middle England?”
Tues-Sat 10am-5pm, Apr 17 to May 15,
free
Usher Gallery
Lindum Road, Lincoln (0152 252 7980)
www.lincolnshire.gov.uk
Serendipity
Exhibition of some of Sri Lanka’s finest
contemporary artists. Work ranges from
sculpture to photography, painting to
printing.
Tues-Sat 10am-5.30pm, Sun 2.30pm-
5pm, ends Apr 16, free
Yorkshire Sculpture Park
West Bretton, Wakefield, West Yorks
(01924 832631) www.ysp.co.uk
Eduodo Chillida
Monumental and medium-sized
sculptures complemented by carvings,
ceramics, graphics and works on paper.
Mon-Sun 11am-5pm, Mar, free
New Delhi-based Subodh Gupta is fast
becoming an established name on the
international art scene. His quirky
figurative work uses globally
recognised brands like the big Mac,
Nike’s ubiquitous tick and the London
underground logo as much as it does
familiar Indian domestic objects like
cooking pots and scooters. The form
varies from a 10-minute video
installation of his naked slimecovered
body utilising the latest in hitech
gadgetry, to simple metal casts
of bamboo sticks. Gupta was featured
in the prestigious First Fukuoka Asian
Art Triennale which heralded a cool
new dawn in the appreciation of
contemporary art from the
subcontinent and is now opening his
first solo show in London. SW
The Showroom, London E2,
Mar 31 to May 9, free
FOCUS: Subodh Gupta
ublic architecture may be a profession not
to be entered lightly by young upstarts, but
it appears David Adjaye never read the
rulebook. Over the past 10 years, the 36-
year-old Royal College of Art graduate has
made his mark on London’s landscape
with some extraordinary structures.
These range from the effortlessly cool
Social Bar, to a black box house for art duo
Tim Noble and Sue Webster.
But it was his design for a house in
Whitechapel, in which no roof, bricks or
windows were visible, that brought Adjaye
serious critical recognition. A brooding
dark shroud, this simple structure was a
striking alternative to terrace living.
More recently Adjaye has been
collaborating with the artist Chris Ofili and
designed INIVA, the first national centre
for culturally diverse visual arts. He is set
to conquer Boston and New York with a
Performing Arts Centre and a Museum of
Contemporary Art and will also be
designing Oslo’s Nobel Peace Centre.
However, in an interview in the Guardian,
Adjaye described the architectural world as
“the most closed, middle-class, middleaged,
trust-fund profession you could ever
be in”. He also voiced concerns over the
way people have a tendency to see
architecture purely as a functional
medium.“Buildings are deeply emotive
structures which form our psyche.”
His new retrospective, Asymmetrical
Chamber, contains photographs and
drawings outlining his approach to
celebrating the confusion of city living. JL
Cube, Liverpool, to Mar 8, free
P
FOCUS:David Adjaye
Above, Asymetric
chamber, work by
David Adjaye at Cube,
Liverpool
The world-acclaimed architect reveals his fascination with stark
modernism, and the power of buildings, in his first retrospective
Lyndon Douglas

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Coke’s ad in Times Square.
June 8, 2006
Changing the Light Bulb
Changing the Light Bulb
Fast Growth in Once-Staid Industry
By EVAN RAMSTAD and KATHRYN KRANHOLD
June 8, 2006; Page B1
The future of lighting is in chips.
Light-emitting diodes — those tiny, chip-based lights that for years have
served as the power indicator on stereos and coffee-makers — are
shaking up the global lighting industry like nothing since fluorescent bulbs emerged just after World War
II.
The spread of LEDs into a wider array of products poses new challenges for Philips Electronics NV,
of Amsterdam; Siemens AG’s Osram unit, based in Munich, Germany; and General Electric Co., of
Fairfield, Conn. The three have dominated every step of making a light bulb, from tungsten mining to retail
promotions, for more than a century. But the LED arena is wide open, with the big multinationals going
up against start-up manufacturers in core chip technology and against niche producers of finished
products — far more competition than they faced in traditional lighting.
A traditional light bulb uses an electrified wire filament in a vacuum tube. An
LED, on the other hand, is a semiconductor chip that, when zapped with
electricity, emits light. The color of the light depends on the material at the
base of the chip. Like computer chips, LEDs can be very small — several
could fit on fingernail — and they can be programmed by software to light
up, for example, a stadium scoreboard.
Such flexibility first pushed LEDs into applications where traditional bulbs
wouldn’t work. Now, high-power LEDs are taking the place of bulbs,
showing up in cellphones, cars, televisions and elsewhere in homes, the light
bulb’s stronghold.
LEDs consume less electricity than many other types of lights and last longer
than most — around 10 years or so. Like other types of chips, their cost is
falling and performance is improving as manufacturers make advances in
materials and factory processes. “It’s going to open up and revolutionize the
way we use and think about lighting,” says Robert Steele, an analyst with Strategies Unlimited, a U.S.
market-research firm that specializes in LEDs.
WSJ.com – Changing the Light Bulb http://online.wsj.com/article_print/SB114973417663874578.html
2 of 3 6/12/2006 9:51 AM
Miami Dolphins’ end-zone screen
Cellphones are the biggest new LED market, lighting up keypads and liquid crystal displays. (Computer
screens, in contrast, rely on fluorescent bulbs for light.) Sales of high-brightness LEDs, the kind used in
the new products, are estimated to be $4 billion to $5 billion this year. Sales are expected to hit $10
billion by the end of the decade.
Among the new applications fueling LED growth: Drivers of the new Ford Motor Co. Mustang can use
the “MyColor” feature to change the color of the lighting on their LED-laden dashboard. (A small line of
red, green and blue LEDs can, in varying combinations, produce 125 colors.) Boeing Corp. plans to use
LEDs throughout the interior of its new 787 Dreamliner commercial jet, creating lighting environments that
are supposed to help international travelers adjust to time-zone changes. Owners of a Louisville, Ky.,
restaurant, Proof On Main, eliminated dangling light bulbs and replaced them with LED lighting that
changes from amber in the morning to violet late at night. Already, some traffic signals in cities in the U.S.
and China use LED fixtures that switch between red, yellow and green, instead of separate colored
bulbs.
Philips is selling flameless candles, with LEDs providing the
“flickering” light source. It also is experimenting with LED-based lights
in the shape of bulbs that fit into existing lamps and offer a twist:
Squeezing or tapping the bulb turns it on or off, or makes it change
color. (LEDs don’t get hot because they use so little energy.) And
Philips is developing a remote-controlled LED room-lighting system.
LEDs’ rising influence is most visible in the growth of companies
working on the basic technology. Philips Electronics’ Lumileds, Nichia
Chemical Corp. and Toyoda Gosei Co., of Japan, and Cree Inc., of Durham, N.C., produce LED chips
and sell them to firms that build finished lights. In Asia, some packages for LED flashlights made by
Energizer Holdings Inc. are marked “LED by Nichia” — a marketing ploy similar to the “Intel Inside”
sticker on a computer.
Some start-ups are establishing early leads in market niches. Canada’s Carmanah Technologies Corp.
married LEDs with solar panels for marine buoys. It later expanded into aviation, selling easy-installation
runway lights to the U.S. military in Afghanistan and elsewhere.
The technology has driven Daktronics Inc. of Brookings, S.D., the largest U.S. maker of scoreboards,
into other types of outdoor signs, including some in New York’s Times Square and London’s Piccadilly
Circus. And LEDs have replaced incandescent light bulbs on many high school scoreboards. “It’s a much
more cost-effective and much better energy source,” says Chief Executive Jim Morgan.
Daktronics has edged ahead of an Asian rival, Lighthouse Technologies, of Hong Kong, in a race to
make the biggest LED screen. Two months ago, Daktronics unveiled a 50-foot-high by 140-foot-wide
screen for Dolphin Stadium in Miami, beating Lighthouse’s 132-foot screen, which sits above touristy
Nathan Road in Hong Kong.
A GE engineer, Nick Holonyak Jr., built the first LED in 1962, and the company patented the discovery.
Among the first big uses for LEDs were calculators, and manufacturer Hewlett-Packard Co. eventually
bought GE’s patent.
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3 of 3 6/12/2006 9:51 AM
Philips Electronics’ LED light ‘bulbs’ change color when squeezed.
But the technology remained on the
fringes of industry for decades.
Nichia and Cree changed that in the
1990s by broadening the LED color
palette, which previously had been
limited to red, yellow and green. The
breakthrough came in 1993, when Nichia, Toyoda Gosei (part-owned by Toyota Motor Co.) and,
soon afterward, Cree conquered blue, marking the final step to creating combinations that would fill out
the color spectrum, including white.
Major manufacturers took notice. In 1999, GE formed GELcore, a venture with chip maker Emcore
Corp., to get back into the LED business. The joint venture is looking to develop the perfect-white
lighting system, which could be used as general illumination in retail stores, industrial buildings and, some
day, homes.
“The game for us is white,” says Michael Petras, vice president of GE’s commercial- and
industrial-lighting sales. “It’s the lighting market.”
Nichia remains the biggest force in overall production of LED chips. Leading in the production of
high-powered chips are Osram Opto Semiconductors and Lumileds, a former joint venture of Philips
Electronics and the Hewlett-Packard spinoff Agilent Technologies Inc. and now 100% owned by
Philips. Gerard Kleisterlee, Philips’s CEO, says one need only look at the history of other electronics
markets to know how varied the future may get.
“We were founded around the manufacture of incandescent light, and that vacuum tube produced other
vacuum tubes for radios and picture tubes for TVs,” Mr. Kleisterlee says. Radio tubes gave way to
transistors, and TV tubes to liquid-crystal displays. “Now,” he says, “finally that same thing starts to
happen to lighting.”
Write to Evan Ramstad at evan.ramstad@wsj.com1 and Kathryn Kranhold at
kathryn.kranhold@wsj.com2
URL for this article:
http://online.wsj.com/article/SB114973417663874578.html
Hyperlinks in this Article:
(1) mailto:evan.ramstad@wsj.com
(2) mailto:kathryn.kranhold@wsj.com
Copyright 2006 Dow Jones & Company, Inc. All Rights Reserved
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S T E P H E N WI R T Z G A L L E R Y
STEPHEN WIRTZ GALLERY, INC. 49 GEARY STREET SAN FRANCISCO, CALIFORNIA 94108
TELEPHONE (415) 433-6879 FAX (415) 433-1608 EMAIL SWG@WIRTZGALLERY.COM
FOR IMMEDIATE RELEASE Contact: Julie Casemore, (415) 433-6879, julie@wirtzgallery.com
CATHERINE WAGNER
A Narrative History of the Light Bulb
Exhibition dates: March 28 – April 28, 2007
Opening reception for the artist, Thursday, April 5, 2007, 5:30 – 7:30 PM
Stephen Wirtz Gallery presents A Narrative History of the Light Bulb, a new series of photographs by Catherine Wagner.
While in residence at the Baltimore Museum of Industry during the last two years, Catherine Wagner was given access to
their 50,000+ collection of historic light bulbs, one of the premier collections of vintage and antique light bulbs in the United
States, with lights dating from the early 19th century. The resulting series of photographs titled A Narrative History of the
Light Bulb embodies both sculptural installation and photography. Wagner creates arrangements of bulbs that she then
photographs with an 8 by 10 view camera in order to record the glass enclosures and the delicate filaments in stunning detail.
Wagner’s work has long been noted for its investigation of the dissemination of knowledge and the construction of culture
and these new works follow in her trajectory of providing access to the close scrutiny of scientific objects.
These works are records of historical light bulb classification as well as narrative landscapes of metaphor rich objects that
borrow from the history of the still life. With a keen eye toward Morandi, Wagner utilizes similar strategies of grouping
familiar objects in beautiful, compelling installations. Some are based on scientific indexes, such as Early Tungsten or
Carbon Filaments 1900- 1910; others are constructed more lyrically, with sensitivity to the implied stories in the groupings
of bulbs. Wagner employs an intuitive approach, cataloging them by color, form, or aesthetic with examples that include an
installation of varying blue bulbs entitled, Homage to Yves Klein, and the architecturally based collection entitled Utopia,
which invokes ideal cityscapes. Green Energy involves a double entendre: the topical need for our technology to become
more sustainable, and also a metaphor our landscape.
Wagner focus on the invention and history of the light bulb and its place as a cultural indicator follows from her long-term
interest in the phenomenon of light as evidenced by past projects such as Cross Sections, Pomegranate Wall (San Jose
Museum of Art, 2001,) the installation of Home and Other Stories (a constructed light and photographic installation at
LACMA, 1993,) as well as her over thirty year career in photography, a medium inherently dependant on light.
Wagner was named one of Time magazine’s Fine Arts Innovators of the Year for 2001. Her work is represented in numerous
public collections including the Museum of Modern Art, New York; the Whitney Museum of American Art, New York; the
Museum of Contemporary Art, Los Angeles; the Los Angeles County Museum of Art; among others. Monographs include
Cross Sections (2002), Art & Science: Investigating Matter (1996), Home and Other Stories (1993), and American
Classroom (1988).
Stephen Wirtz Gallery is located at 49 Geary St., 3rd Fl., San Francisco, CA 94108, (415) 433-6879, Gallery hours are
Tuesday-Friday, 9:30-5:30, Saturday 10:30-5:30.

Seeing the Light: The Physics and Materials Science of the Incandescent Light Bulb
This unit consists of an interlinked series of 6 multi-part experiments using inexpensive materials such as lights bulbs, heater wire, and an ohmmeter. In the first experiment, students discover that Ohm’s law doesn’t appear to be valid for the filament resistance of the light bulb. They then develop the understanding that this arises from the change in filament resistance with temperature. This experiment connects commonly used technology – the light bulb – with the mathematics of Ohm’s law as well as with the dependence of the electrical properties of materials on their composition, length, and diameter. In a subsequent series of experiments, students investigate a 3-way bulb, a 3-way switch, and then a 3-way bulb in a 3-way switch socket. They develop the understanding – using observation, logical reasoning, and mathematical modeling – that a 3-way bulb consists of 2 filaments which are connected in parallel at the highest wattage setting. In the third experiment, students design a light bulb and describe the fabrication steps necessary to construct it; students are given some basic engineering information before attempting the experiment. They then dissect a light bulb and determine how close their earlier design resembles a real bulb. Finally, they must design and construct a light bulb that operates in air using materials that are similar to those found in a light bulb, but are oxidation resistant. These materials are available as a kit from the General Atomics Sciences Education Foundation as GASEF #013. GASEF #013 contains 10 20-cm long pieces of 0.003 inch diameter Kanthal AF wire, 2 20-cm long pieces of 0.010 inch diameter Kanthal AF wire, and 2 20-cm long pieces of 0.020 inch diameter copper wire.

This unit also consists of an extensive introduction with background information into advanced topics such as oxidation resistant materials, blackbody radiation, filament materials, filament environments, and a microscopic view of incandescence. Also explored are a brief history of the development of the light bulb and Edison’s critical role in the methodology of experimental science, which set the subsequent standard for industrial research. A teacher’s guide to all experiments, related mathematical problem sets, and solutions is included the module. This unit provides a natural tie to studies in economics and US history that involve the electrification of society, the industrial revolution, the rivalry between AC and DC distribution systems, and the growth of industrial laboratories. Students require a previous introduction to Ohm’s Law and series and parallel circuits before beginning this unit. These experiments are aimed at grades 7-12, but would also be appropriate for an introductory university physics or materials science course.

This unit relates to the NSES physical science content standards in grades 5-8: “Energy is a property of many substances and is associated with heat, light, electricity … Energy is transferred in many ways. Electrical circuits provide a means of transferring electrical energy when heat. light, sound, and chemical changes are produced;” and in grades 9-12: “Energy can be transferred … in many ways. In some materials, such as metals, electrons flow easily, whereas in insulating material they can hardly flow at all.”

Download Entire Unit (1.1MB PDF)

Section Page
Table of Contents… 2
Correspondence to the National Science Education Standards… 3
Correspondence to the Benchmarks for Science Literacy… 5
Logical Construction of Module… 8
Introduction and Basic Physics… 9
Introduction to Filament Design Parameters… 12
Experiment 1: The Room Temperature Filament Resistance of Different Wattage Bulbs… 14
Experiment 2: The Temperature Dependence of the Resistance of a 100 W Light Bulb… 17
Experiment 3: The Electrical Properties of 3-Way Bulbs… 19
Experiment 4: Light Bulb Design… 24
Experiment 5: Light Bulb Dissection… 26
Experiment 6: Light Bulb Fabrication… 28
Advanced Topic: Oxidation Resistant Materials… 30
Advanced Topic: Blackbody Radiation… 32
Advanced Topic: Filament Material… 33
Advanced Topic: Filament Environment… 35
Advanced Topic: Microscopic View of Incandescence… 36
Advanced Topic: A Brief History: The Edisonian Approach… 37
Problems… 38
Solutions… 39
Reference 44
Materials Required… 45
Appendix… 46
Response to a question about developing the cooling curve (Experiment 2, page 18)

This unit was developed by Dr. Lawrence D. Woolf

webmaster@ga.com

©General Atomics

The Corning Ribbon Machine
For Incandescent Light Bulb Blanks
International Historic Mechanical Engineering Landmark
1983
American Society of Mechanical Engineers
Will Woods And His
Fabulous Machine When William J. Woods first came to work at Corning Glass Works in
1898, there was little — except for his shock of auburn hair — that would have
indicated he was anything out of the ordinary.
Of medium height and weight, 19-year-old Woods — everyone called him Will —
was a newcomer to Corning, N.Y., from the Pittsburgh area where he had been
born in the town of Martinsburg to an Irish mother and a Scottish father. As a
boy, he had learned to blow glass in the Westinghouse Glass Works, one of
many such enterprises which flourished off the abundant coal that underlay the
wooded ridges of western Pennsylvania.
Will Woods had come to Corning to pursue his calling as a glassblower. And
despite his appearance, Will Woods was anything but ordinary.
He was a man with an instinctive fascination for the inner workings of
machinery. Although Woods had little formal education and no training
whatsoever in the mechanical arts, his “open and independent mind,” in the
words of one Corning Glass historian, enabled him to see possibilities hidden to
others of his trade.
It was a time for invention, one of those rare periods in human history when the
activity of man’s mind resulted in technological achievement that forever
changed the face of the earth and man’s outlook upon it.
One of these triumphs was the invention, in 1879 (the year of Will Woods’
birth), of a successful incandescent electric light bulb by Thomas Alva Edison,
the “Wizard of Menlo Park” whose keen intellect and driving spirit also
produced the phonograph, the motion picture and countless other inventions
and improvements.
A BOYISH WILL WOODS DEMONSTRATES
THE GLASSBLOWING
TECHNIQUE THAT
BROUGHT HIM SUCCESS.
1
‘Let There Be
Light Bulbs’
A CORNING INVOICE DATED
1880 SHOWS THE PURCHASE
OF VARIOUS KINDS OF GLASS
TUBING BY THOMAS EDISON
“FOR ELECTRIC LIGHT.”
Aware of the company’s dedication to science and engineering,
Edison had chosen Corning Glass to manufacture the glass envelope for his first
bulbs. The carbon filament that first glowed brightly in his New Jersey
laboratories was enclosed by a bulb produced by Corning glassblowers to
Edison’s specifications.
That first bulb sparked a dream in the minds of many: a world where the sunset
would no longer limit man’s activities, a world where inexpensive electricity
could illuminate even the darkest and most farflung of regions.
Electric light certainly was no myth, but in the years following Edison’s
invention, it proved more difficult to achieve than had been at first anticipated.
Although its possibilities were immediately foreseen, production was difficult
and expensive.
While filaments and bases could be manufactured, glass bulb envelopes could
be made only by hand, or by mouth as it were, by glassblowers skilled in an
ancient trade. These master craftsmen, called gaffers, learned their trade during
a long apprenticeship and were few in number.
2
Towards Automation
AT THE TURN OF THE CENTURY,
A TEAM OF TWO MEN
COULD PRODUCE THREE
GLASS BULBS PER MINUTE.
Working at top speed in the red-orange radiance of a glass-melting tank, a team
of two men, gaffer and assistant, could produce two bulbs per minute in the
glass works of the 1890s. It was clear that, at this speed, Edison’s Age of
Universal Light would be a long time dawning. To complicate matters further,
the hand-blown bulbs were expensive by the standards of the time, so that,
even if large enough quantities could be produced, they would be beyond the
means of most people even in nations that were rapidly developing their
industrial base.
Nevertheless, the concept of the electric light fired the imagination, and people
embraced it eagerly. News of Edison’s remarkable success spread over the globe
with only slightly less speed than that of light itself.
Into this climate stepped young Will Woods, glassblower. In 1907,
eight years after Woods had come to Corning Glass, the company began work
on what was to become known as the “E” Machine, the world’s first automated
process for glass light bulb envelope production.
Automated, but hardly automatic, the Empire “E” Machine (Empire was a
Corning Glass subsidiary founded to design and produce automated glass-making
and finishing machinery) still required workers to “gather” the molten glass by
hand for blowing into bulbs.
By 1913, the “E” Machine was producing glass bulbs at the then- rapid rate of
seven per minute. Corning installed numbers of these machines at its newly
purchased plant in nearby Wellsboro, Pa. — where Will Woods had been
transferred — and the race for automatic light bulb envelope production began
in earnest.
It had indeed become a race. In 1912, even before the “E” Machine began
producing bulbs, Empire engineers had in 1912 begun work on its successor,
appropriately named the “F” Machine. And even earlier, General Electric had
3
A Shovel, A Gob
And A Brainstorm
AN EARLY ATTEMPT AT AUTOMATING
THE BULB-BLOWING
PROCESS RESULTED IN
THIS ODD-LOOKING MACHINE.
THE AIR WAS STILL
SUPPLIED BY LUNG POWER
begun work on its “Westlake” machine, which promised to eclipse the hardworking
“E” types.
The “Westlake” and “F” machines were rotary-type machines, capable of
producing 12, 24 or 48 bulb envelopes during each revolution. Glass was
delivered to the machines as they operated, eliminating the cumbersome and
time-consuming hand-gather system that slowed the operation of the “E”
Machine to a relative crawl. Corning began installing the “F” Machines in its
Wellsboro plant in 1923.
Will Woods was not idle during these years of machine development.
First in Corning and then in Wellsboro, he actively studied the crafthe had
chosen until he had become a master gaffer himself.
Greatly intrigued by the possibilities of electric light and the application of
mechanical technology to the production of light bulbs, Woods had become
instrumental to the success of the slow but effective “E” Machine at Wellsboro.
rising to the post of production superintendent by 1917.
Woods’s production efforts quickly became the stuff of legend. Corning Glass
historian George Buell Hollister records that “With the help of a few bulb
gatherers brought from the Corning plant he manned his battery of machines
with boys from the neighboring farms, taught them to handle the equipment
and in a surprisingly short time transformed them into a body of efficient
workmen.”
Then, in the spring of 1921, Woods conceived the idea that would, if not bring
him fame, at least secure him the enviable reputation of a man of mechanical
genius.
Otto Hilbert, a companion of Woods, wrote in 1979 that Woods saw a shovel
which had been used to collect glass. On that shovel was a still-molten gob of
4
THE “E” MACHINE WAS A
DIRECT ANCESTOR OF THE
RIBBON MACHINE. WILLIAM J
WOODS APPEARS (IN BOW TIE)
IN RIGHT CENTER BACKGROUND.
glass which looked like a light bulb blank.
Another account has it that the shovel had a hole in it, a hole through which the
semi-molten glass had sagged in the shape of a bulb blank.
Whatever the truth, in the spring of 1921, Will Woods suddenly conceived the
revolutionary idea of automatically blowing light bulb blanks through a hole in a
metal plate.
It was a simple idea; simple, but elgant in its simplicity. Woods had gone to
the heart of the matter, and his idea was to change radically the way in which
bulb blanks were – and are – manufactured.
And like all ideas which promise radical change, it was greeted with skepticism
on the part of Woods’s fellow glassblowers, who preferred traditional methods of
making bulb blanks to the newfangled machines that already were taking their
places in the nation’s glass plants. (In Europe, nearly all bulbs still were being
blown by hand.)
5
From Brainstorm To
Bulb Blanks
Nevertheless, an undaunted Woods persevered with his conception and won
the minds of Corning’s engineering staff; the company authorized construction
of a prototype – if indeed one could be constructed – to test Woods’s theory.
That theory, basically, was this: If a gather of molten glass were flattened and
then placed on a plate with a hole of the proper size, the glass might sag through
the hole to form a globular bag. If air were then forced into this bag, it might be
expanded to form the basic shape of a bulb blank. To perfect this shape, a mold
could be closed around it and the air pressure continued.
Then carne the piece de resistance: If a series of such plates were hinged
together to form an “endless chain” or belt, and a flat stream of molten glass
were to be laid on the belt while in motion, perfect blanks might be made in
continuous succession.
Historian Hollister continues: “With this basic idea in mind, Woods started to
experiment with a single plate and a plunger or blowhead by which he could
introduce air into the bag formed by the molten glass sagging through the hole
or orifice in the plate, and after many attempts succeeded in forming bags which
had all the earmarks of the beginnings of good bulb blanks . . .
“The full solution of the problem then resolved itself into the designing of a
mechanism which would first form the desired blanks and, second, conduct
them with properly maintained temperatures and predetermined speed through
the elongating and blowing operations and, finally, to the finished bulb.”
Will Woods had conceived the fabulous Ribbon Machine. The problem of
building one remained.
The building known as Building 9 on Corning’s Pine Street already was
old when Will Woods moved in with his development crew of one person,
6
IN LATER YEARS, WOODS ENJOYED
AN OFFICE – AND A
STRAW BOATER – OF HIS OWN.
David E. Gray. But Gray was no ordinary developer, just as Woods was no
ordinary inventor.
Gray had been trained in mechanical engineering at the Massachusetts Institute
of Technology. Experienced and competent, Gray was in 1922 Corning Glass
Works’ chief engineer and a man with a special interest in the development of
machines to manufacture glass products.
It was Gray who, intrigued with Woods’ idea for a bulb blank machine, had
studied the possibilities and concluded such a machine was practical. Astonished
at the results of his own study, Gray decided to produce the prototype and
found the funds to proceed.
Woods and Gray didn’t know they were working on the Ribbon Machine. On
the origina1 books for the project, the machine was called, in code, the “399
Machine.” Later, it became known, as if there were no other machine in the
world, as “The Corning Machine.”
7
The Ribbon Machine:
A Runaway Success
Indeed, there was no other machine in the world like the one Woods and Gray
were constructing in Building 9.
Woods’s conception proved remarkably adaptable to design and construction,
and the older machines had provided a wealth of experience that guided the
Ribbon Machine’s developers to a successful conclusion.
By 1925, it had become clear to Woods and Gray – and to others at Corning –
that the Ribbon Machine had become a reality. By 1926 the ungainly creature
began to produce bulb blanks, slowly at first, but with increasing rapidity. The
derisive hoots which had greeted Woods’s idea gave way to awe.
As it emerged from its creative metamorphosis in the cocoon of
Building 9, the first Ribbon Machine presented an awesome sight.
A glass melting tank sat above one end of the machine, feeding a stream of
molten glass from its forehearth down between two metal drums, which
flattened the glass into a thick, glowing ribbon. This yellow-orange ribbon was
laid onto a series of square plates, each with a small hole in its center, which
were linked together in the manner of a bicycle chain and driven by sprockets at
either end of the oval.
As soon as the glass ribbon was laid on the chain, the glass began to sink through
the holes, giving nascent form to the future bulb blanks. A chained series of
moving plungers above the chain descended on the hot ribbon, pushing
compressed air into the sagging glass. And a third chain, below and inside the
first, thrust up a series of split molds which snapped together around the
forming glass to give final shape to the bulb blanks before unsnapping just as
quickly to revea1 the familiar light bulb configuration.
For each bulb blank, the entire forming operation lasted but a few seconds,
resulting in what one observer termed “a veritable shower” of finished bulbs as
8
Bulbs For The Lamps
Of The World
THE CORNING RIBBON MACHINE:
DELIVERS FINISHED
BULBS AT DIZZYING RATES UP
TO 2000 PER MINITE.
the blanks were tapped off a fraction of a second apart.
The first production runs of the prototype Ribbon Machine were astonishing,
especially to those used to the slower “E” and “F” machines. Actual records
show runs of around 400,000 blanks in 24 hours, almost five times the output of
the earlier machines.
In the 1890s only 20 to 30 years before the advent of the Ribbon
Machine, the slogan of American merchants seeking to participate in the
Chinese market had been “Oil for the lamps of China.”
By 1926, when the first Ribbon Machines were installed in Corning’s Wellsboro
plant, that slogan was irrevocably dated. The new machine would provide bulbs
for the lamps of the world. And it was becoming more and more apparent that it
wouldn’t take very many Ribbon Machines to provide those bulbs, either.
The Ribbon Machine was a marvel of efficiency. The astonishing figures of the
early production runs were, by 1930, almost ancient history as the Ribbon
Machine reached, and then surpassed, 1 million bulb blanks in 24 hours. This
figure, in turn, receded as the Ribbon Machine was fine-tuned to its capacity of
some 2,000 bulb blanks per minute, or nearly 3 million blanks in 24 hours, for
smaller-sized bulbs.
With few mechanical changes, the Corning Ribbon Machine remains the
highest state of the technology today, more than 50 years after its conception
and construction in the old building, long since vanished, on Corning’s Pine
Street. Fewer than 15 Ribbon Machines now supply the entire world’s
consumption of glass blanks for incandescent light bulbs, with the exception of
some small blanks that are hand-made for specialty lamps.
9
Ribbon Machines Today
ROLLERS SQUEEZE HOT
GLASS FROM MELTING ‘IANK
INTO THE CHARACTERISTIC
“RIBBON” OF ‘IHE CORNING
RIBBON MACHINE.
HOT GLASS RIBBON SAGS
‘IHROUGH HOLES IN PLATES
BEFORE COMPRESSED AIR
JETS COMPLETE THE BLOWING
PROCESS.
Ribbon Machines are flourishing in England, Belgium, Hungary, the Soviet
Union, Japan and Iraq, providing inexpensive light bulb components for the
light which now illuminates homes from the grandest of manors to the meanest
of hovels.
Today, there are two different types of Ribbon Machine, the lowervolume
Model 100 and the faster Model 400. Both have chain pitches of three
inches and manufacture bulb envelopes in weights from eight to 45 grams, with
maximum and minimum outer diameters of 67 and 19 millimeters respectively
and maximum and minimum bulb lengths of 171.5 millimeters and 50
millimeters.
Both machines have the ability to produce irregular shapes, and, by using a
process known as the nonrotating-mold hot-iron process, both may manufacture
nonsymmetrical shapes.
The 25foot-long Model 100 Ribbon Machine, operating at a standard speed of
275-300 pieces per minute (ED 60/A-type bulb blanks) can produce 100 million
perfect bulb envelopes per year. Operating at a standard speed of 1000-1100
pieces per minute (ED 60/A blanks), the Model 400 can manufacture 400
million bulb envelopes per year.
These Ribbon Machines are little changed from the prototype model built by
Woods and Gray. On the original, the holed plates were split, but on the
modern versions, these plates are in one piece.
The single problem encountered by Woods and Gray – breakage of the blanks
as they were separated from the plates – was solved before 1930 with a tap-off
system that delivers a quick blow to the blank at the point where it joins the
orifice plate, allowing a clean break with minimum breakage.
10
MOLDS CLOSE AROUND SAGGING
GLASS TO GIVE FINAL
FORM TO BULB BLANKS.
Coda
Today’s Ribbon Machines manufacture not only light bulb blanks, but a wide
variety of other glass components, including such seemingly divergent items as
vacuum bottles and clock domes.
After 1930, it quickly was recognized that the Ribbon Machine would become
the standard manufacturing technology for light bulb blanks. Corning retired its
almost-new “F” Machines in favor of the quicker technology. General Electric
did the same with its once-formidable “Westlake” machines, licensing the
Ribbon Machine technology in its stead. By the decade’s end, the Ribbon
Machine had assumed its rightful place as the sole machine for production of
incandescent light bulb blanks.
Even though Corning kept its “E” Machines in use into the 1940s for the
production of items unrelated to lighting, an era that had begun with Edison had
ended in the ultimate triumph of Will Woods and his marvelous machine.
Will Woods wasn’t quite finished, however. Before his death on
Christmas Eve, 1937, he also perfected what became known as the Woods
Updraw Tubing Machine for the fully automatic production of thermometer
tubing. But that’s another story.
Corning Glass Works slowly is leaving the once-profitable business of
manufacturing glass light bulb blanks. The famed specialty glass firm continues
to license the Ribbon Machine technology worldwide, however, through its
subsidiary company, Corning Engineering. And Corning has not forgotten its
involvement with light – among its newer products are optical waveguides, hairthin
strands of glass that permit the long-distance transmittance of thousands of
simultaneous telephone calls using pulsed light.
11
The company was proud to learn that the American Society of Mechanical
Engineers had designated the Ribbon Machine as the tenth International
Historic Mechanical Engineering Landmark, a ranking which places it on a scale
with the first operational steam engine in considering mechanical devices that
have changed the face of history.
Will Woods, the unassuming and unsung hero of the Age of Universal Light,
would surely have been gratified.
SCHEMATIC RENDERING
SHOWS AN ENGINEERING IMPROVEMENT.
PLATES NOW
MOVE ON CHAIN AROUND RIBBON
MACHINE.
12
International Historic Mechanical Engineering Landmark
1983
American Society of Mechanical Engineers
H081
CORNING

76 IEEE power & energy magazine january/february 2005

more as an inventive genius than as a
businessman. Some may know he was
granted more patents by the U.S.
Patent and Trademark Office than any
other person, 1,093 patents to be
exact. Fewer know that he also started
over 100 businesses and partnerships,
some of which survive to this day.
Edison is known around the world for
inventing a practical and commercially
successful incandescent electric
light bulb. However, Edison also
invented (or helped invent) entire
industries, including the electric,
music, motion picture, and battery
industries. We will look at how Edison
succeeded as an inventor primarily
because he was better than his competitors
at marshaling the forces and
institutions of business.
Myth Versus the Real
Thomas Edison
Myths about Edison abound, with one
of the most popular being that he was
a terrible businessman more likely to
hit a “lucky streak” than to intentionally
manage the innovation process.
Compounding this misconception, the
1940 film Edison, the Man, starring
Spencer Tracy, portrayed Edison as
uninterested in and confused by the
financial side of invention. Nothing
could be further from the truth. Edison
(see Figure 1) was keenly aware
of the economic considerations of his
inventions and could even be critical
of his contemporaries for ignoring
business realities.
Edison’s business story began
before he was a teenager and extended
almost until the day of his death. By
the age of 12, he had begun selling
newspapers and candy on the Grand
Trunk Railroad that connected Detroit
to his hometown of Port Huron,
Michigan. Apparently discontented
with selling other people’s newspapers,
he began printing his own publication,
The Weekly Herald, and selling
it on the train as well. At the same
time, he managed a vegetable stand
and transported some of the produce
to Detroit for resale where it brought a
higher price. Edison exhibited such
entrepreneurial ability throughout his
life, and it proved crucial to his many
achievements. We will sift through
Edison’s life and highlight a few of
the factors that contributed to his business
success. Put simply, Edison succeeded
more than other inventors of
his day primarily because he was a
better businessman.
Invention Is a
Commercial Process
Edison had little desire to become a
“business tycoon” and spend all his
time overseeing a sprawling industrial
empire. He preferred to remain in the
laboratory, and his true business was
the innovation of new products, at
which he was highly successful.
Although he was often involved in key
management decisions of the companies
established to capitalize on his
inventions, Edison saw his role primarily
as that of inventor. Furthermore,
the roots of his inventive practices can
be traced to the time he spent in the
emerging telegraph industry.
Edison began studying telegraphy
in the autumn of 1862, when he was
15 years old. Within a few years, he
had begun working for the Western
Union Company and inventing
improved telegraph equipment. In
1868, he settled in Boston and began
creating a name for himself within the
telegraph industry. Edison filed his
first telegraph patent in 1869 and by
1871 was referred to as “the best electro-
mechanician in the country” by
Western Union President William
Orton. Over the course of his life, Edison
would file only slightly fewer telegraph
patents (186 patents) than he
Blaine McCormick and Paul Israel
history
underrated entrepreneur
Thomas Edison’s overlooked business story
1540-7977/05/$20.00©2005 IEEE
figure 1. Thomas Edison in 1881 at
34 years of age. (Photo courtesy of
the Edison National Historic Site.)
january/february 2005 IEEE power & energy magazine
filed in the field of recorded sound
(199 patents). This is ironic given that
few people acknowledge Edison as a
major force in the early telegraph
industry. In part, this perception arises
from Edison’s role as a contract inventor
who relied on others to introduce
his inventions.
Edison’s life revolved almost solely
around the telegraph industry from his
introduction to telegraphy in 1862
until he conceived the idea for the
electric pen in June
1875. His work in the
telegraph industry contributed
greatly to his
entrepreneurial success
in other industries later
in his life. Furthermore,
Edison’s experience
in the telegraph
industry gave him a
deep well of business
experience from which
he could draw and
which other inventors
of his day lacked.
An important moment
in Edison’s life
accompanied the receipt
of his first patent
in 1869. The patent
was for an electric vote
recorder that allowed
members of legislative
bodies to tally votes
using electricity rather than through
the slow process of roll call. Edison
hoped to get some money for the
invention but was firmly rejected on
his first sales call to the Massachusetts
state legislature. He tried next to sell
the invention to the federal government
in Washington, DC, but was told,
“Young man, that is just what we do
not want.” The business-minded Edison
had overestimated the importance
of speed in the slow world of legislative
filibustering. On his way home,
Edison resolved never to invent anything
that did not have what he called
“commercial demand.”
For the most part, this proved to be
a highly successful strategy ensuring
that Edison’s goal was not just invention
but innovation. During the
research and development work on a
new technology, he paid close attention
to ways to lower operating and
manufacturing costs and methods of
adapting the technology to the needs
of users. And once he began commercial
introduction of a new technology,
Edison devoted a great deal of attention
to improving the manufacturing
processes to reduce the cost of the
new technology. Also, he continued
research and development so that he
could better adapt his products to the
needs of users. Figure 2 shows Edison’s
first lamp factory, where he
manufactured his incandescent lighting
system.
Attention to these market-driven
issues enabled Edison to successfully
innovate new technologies and establish
highly successful companies in
the phonograph, motion picture,
cement, and storage battery industries.
His only notable failure was an effort
to refine low-grade iron ore, on which
he spent millions of dollars of his own
money. Yet, Edison could absorb the
cost of this failure because he was
highly successful in other endeavors.
And in each instance, Edison relied on
highly competent managers to oversee
these businesses.
Superior Understanding
of the Patent and
Legal System
Edison filed his first patent application
in 1868 at the age of 21. Furthermore,
he filed well over 100 patents prior to
achieving international fame with the
invention of the phonograph in 1878.
These ten years of patent activity in
the telegraph industry
taught Edison how to
navigate the patent and
legal system in America.
By the time he
invented the phonograph
and the practical
incandescent electric
light bulb, Edison was
better prepared than his
competitors to capture
the gains associated
with his new inventions.
Figure 3 shows Edison’s
U.S. patents by
execution date. Readers
will note that although
he invented the practical
electric light bulb in
1879, there’s a spike in
patent activity in the
four years that follow.
Other spikes occur during
his telegraphy years
in the early 1870s and again in the late
1880s and early 1890s. Rather than
remaining flat, Edison’s patent activity
experienced peaks and valleys depending
on his efforts to improve the commercial
viability of an invention. One
of his basic strategies is captured in
this statement about some of his electrical
patents. Edison noted, “The
patents I am now taking are more valuable
than those already taken. Those
already taken were to secure if possible
the science of the thing. Those I am
now taking are commercial.”
Edison learned very early during
his work in the telegraph industry that
there’s more than one way to solve a
problem. Working as a contract inventor
for competing companies, Edison
77
figure 2. Edison established his first lamp factory near his laboratory
in Menlo Park, New Jersey, so that he could refine the manufacturing
process and improve the lamps as he moved to commercial
introduction of his lighting system. (Photo courtesy of the Edison
National Historic Site.)
found it necessary to take some care in
juggling both his own interests and the
interests of those paying for his inventive
work. Yet, working on multiple
projects also stimulated him. This
became a hallmark of his inventive
style, as ideas and devices from one
experiment or design influenced
another. In Edison’s words, if he
reached a dead end on one project, he
would “just put it aside and go at
something else; and the first thing I
know the very idea I wanted will come
to me. Then I drop the other and go
back to it and work it out.”
In fact, Edison frequently used
experiments in one direction to suggest
ideas for other lines of research
and often drew on elements of one
technology to improve another. Sometimes,
he did no more than note ideas
that emerged from such explorations
in his notebooks or patent caveats, but
at other times they became the basis
for a new research project. A related
characteristic was Edison’s tendency
to conceive seemingly endless variations
in the design for a particular
device. His early notebooks often contain
the statement “I do not wish to
confine myself to any particular
device.” These words represented not
only a legalistic phrase associated
with the patent system but also corresponded
to Edison’s pattern of sketching
numerous alternative solutions to a
particular problem.
Edison’s sophisticated understanding
of the patent system grew out of
his experience as a contract inventor in
the telegraph industry. As an inventor
for the Gold and Stock Telegraph
Company, Edison learned from its
president, Marshall Lefferts, that by
acquiring all of the key patents on
printing telegraph technology, the
company was able to control the field
of market reporting. Soon after Edison
told William Orton, president of Western
Union, that he could readily invent
around the patented system of duplex
telegraphy (for sending two messages
simultaneously over a single wire) that
the company had recently put on its
lines. Boasting that “the business of
making a duplex [w]as a very trifling
affair,” Edison showed Orton a variety
of alternative designs. Edison was
hired to invent duplexes “as an insurance
against other parties using them.”
Edison’s work on duplexes led to his
most important telegraph invention,
the quadruplex telegraph, which
enabled four messages to be sent
simultaneously over one wire.
Superior Exploitation
of Capital Markets
It was previously mentioned that Edison
had much greater resources for
research and development than any
other inventor of his time. He had
established his name as a telegraph
inventor, and this earned him access to
financial support from Western Union
financiers such as J.P. Morgan and
William Vanderbilt and company officials
such as Norvin Green. Green was
also the first president of the Edison
Electric Light Company, which was
established to support Edison’s work.
Among those who established the
company were directors of Western
Union and partners in Morgan’s firm.
These men were willing to back Edison’s
venture in electric lighting
because of his previous work for Western
Union and due to his enhanced
reputation as an inventive “wizard”
following his invention of the phonograph.
Edison’s reputation was a product
of both his creative technical feats
and his facility for self-promotion.
One good example of Edison’s talent
for exploiting capital markets
occurred during the invention of the
practical electric light. Contrary to
popular perception, Edison was not
the first person to have a working
electric light bulb. In fact, historians
have documented the fact that more
than 20 people preceded Edison with a
working electric light bulb, some
being his contemporaries. Edison
began experimenting with electric
light in August 1878, long after competitors
like Joseph Swan, Moses
Farmer, and William Sawyer (to name
a few) began their work.
So what enabled Edison to start
later, yet leapfrog his competitors to
become known as the inventor of the
electric light bulb? One explanation is
that Edison was better positioned to
exploit the capital markets at the time.
First, Edison had a solid understanding
of the entire system of electricity that
was necessary to support an electric
light bulb. His work in the telegraph
industry greatly contributed to his
understanding of various electrical
apparatus and electrical systems. Second,
Edison was fresh from the invention
of the phonograph the previous
year, a time at which the New York
Daily Graphic dubbed him the “Wizard
of Menlo Park,” as shown in Figure 4.
He had toured the country, met President
Rutherford B. Hayes, and received
overwhelming amounts of press for his
admittedly unprecedented invention.
78 IEEE power & energy magazine january/february 2005
figure 3. Edison’s U.S. patents by execution date.
120
110
100
90
80
70
60
50
40
30
20
10
0
1868 1875 1880 1885 1890 1895 1900 1905 1910 1915 1920 1925 1930
january/february 2005 IEEE power & energy magazine
Finally, Edison possessed better
facilities than anybody else and was
supported by a team of workers
ready to tackle the invention of the
practical electric light bulb and the
development of a comprehensive
electric power system. No other
inventor had anything approaching
the scope of Edison’s well-equipped
Menlo Park lab, shown in Figure 5,
and no other business leader in the
country had a more experienced team
of inventors. These three things,
knowledge, reputation, and facilities,
allowed Edison to corner the existing
capital market for research and
development funds for the electric
light bulb. Records indicate that Edison
received about US$130,000 of
venture capital in the two and a half
years of active research and development
between September 1878 and
March 1881. None of his competitors
received anything remotely close to
this amount. Using these funds, Edison
purchased new equipment for his
laboratory, built a new and larger
experimental machine shop, and
added a combined office and library
building that he stocked with books
and journals that had previously been
beyond his means to purchase. Given
that many of his competitors were
self-financed, relatively unknown in
comparison, and poorly equipped,
it’s no wonder that Edison outmaneuvered
them.
Conclusion
A recent poll of business historians
published in Business History Review
ranked Edison fifth in a list of the ten
greatest entrepreneurs and business
people in American history. In this
poll, Edison’s name appeared with
giants of enterprise such as Henry
Ford, Bill Gates, Sam Walton, and
Alfred Sloan. A broad range of historians
clearly consider Edison’s business
story to have merit, as he not
only placed in the top five but trailed
only Henry Ford and John D. Rockefeller
in the number of first place
votes received.
Scholars and historians have most
likely condemned Edison to business
ignominy for the act of creating vast
amounts of wealth and letting much
of it slip through his fingers. Although
there is some truth to this observation,
it would be shortsighted to continue
this trend as it focuses entirely on
what Edison failed to do (i.e., capture
wealth) and almost completely
ignores his many business successes.
Continuing to view Edison as the
great American inventor who paid no
attention to business conforms more
to the conventions of Hollywood than
the historical record. As columnist
Allen Barra warned (with a nod to
George Santayana), “Those who do
not study history are forced to get it
from Hollywood.”
For Further Reading
P. Israel, Edison: A Life of Invention.
New York:Wiley, 1998.
A. Millard, Edison and the Business
of Innovation. Baltimore, MD:
Johns Hopkins, 1990.
B. McCormick, At Work with
Thomas Edison. Irvine, CA: Entrepreneur,
2001
The Papers of Thomas A. Edison
(vol. 1-5). Baltimore, MD: Johns Hopkins
[Online]. Available: http://edison.
rutgers.edu
79
figure 4. Following the introduction
of the phonograph, Edison was
dubbed the “Wizard of Menlo Park”
in July 1878 by New York Daily
Graphic reporter William Croffut.
figure 5. With funds from the Edison Electric Light Company, Edison expanded
the original Menlo Park laboratory (center) by adding a larger machine shop
(rear) and a library-office. This painting also depicts the experimental electric
railroad (right) that he was working on as part of his plan to sell power as well
as light. (Photo courtesy of the Edison National Historic Site.) p&e

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