Karrie Jacobs | Dialogues

A Thousand Points on Light: Part I

Night sky over Puget Sound, 2009. Photo: Dan Mauch

At the same moment that we are increasingly conscious of the dangers that man-made lighting poses to birds, plants, wildlife and our own biological rhythms, we’ve become ever more enthralled with the artistic and architectural power of radiance. Whether we’re talking Las Vegas, Shanghai or New York, the seductive draw of urban glow has never been greater. Below, Susan Harder, a leader of the Dark-Sky movement, and Leni Schwendinger, a crusading lighting designer, attempt to tackle the issues of light pollution in urban, suburban and rural settings. Susan, whose organization advocates for greater regulation of lighting practices and Leni, known for creatively illuminating landmarks such as the Coney Island Parachute Jump, would seem to sit on opposite sides of the fence. But as this discussion reveals, they both agree that a more thoughtful approach to lighting, rather than an across-the-board reduction, is the best way to tackle the problem.

Coney Island Parachute Jump illuminated by Leni Schwendinger Light Projects. Photo: Archphoto

Karrie Jacobs
I’d like to begin with a quote from “Our Vanishing Night,” an article by Verlyn Klinkenborg that appeared in National Geographic last year:

Of all the pollutions we face, light pollution is perhaps the most easily remedied. Simple changes in lighting design and installation yield immediate changes in the amount of light spilled into the atmosphere and, often, immediate energy savings.

The quote suggests two questions that I thought would get the ball rolling:

1. Are the changes that need to be made to lighting design and equipment indeed simple?

2. Is there any kind of consensus as to which lighting practices constitute pollution and which are essential?

Susan Harder
I agree with Mr. Klinkenborg. I’ve changed a great many outdoor lighting fixtures and have been able to provide a return on investment within five years. In one case of a post-top streetlight on Main Street in East Hampton, New York, we halved the wattage and provided better-quality light on the ground. As a benefit, the residents felt that the new fixture reduced glare and was more attractive. It also reduced the light hitting treetops and entering peoples’ bedrooms. In such cases, not only is money saved through energy conservation, but “light pollution” (misdirected, excessive, unshielded or unnecessary night lighting that produces glare, light trespass and sky-glow) is greatly reduced. We are lucky that correcting light pollution is so cost-effective.

So in answer to your first question, yes, changes that need to be made in lighting design and equipment are simple, if they are followed. Good equipment exists (and more is being developed), as does good design criteria. Without regulations and municipal policies to mandate better lighting practices, however, better lighting will not result. While you can see many good lighting-design installations in New York City, for example, they are usually the work of an “enlightened” lighting designer who has been hired for the project. New York, like many major cities, has few to no regulations for outdoor lighting. Regulations will allow a review process prior to construction to assure a better type of light fixture, the correct amount of light to see well and automated shutoffs to extinguish the light when it is not needed. The type of light bulb should be energy-efficient while not adding unnecessarily to sky-glow and maintenance costs.

As to your second question, essential lighting need not result in light pollution. Light pollution is the result of no criteria, poor design, no lighting plan review and incorrect installation. Unfortunately, most of our installed outdoor lighting produces light pollution in all its forms.

Acceptable and Unacceptable Lighting Fixtures
Acceptable and Unacceptable Lighting Fixtures for East Hampton, NY. Courtesy Susan Harder

Leni Schwendinger
Mr. Klinkenborg presents a dire vision of “light spilling into the atmosphere” — purportedly analogous to dumping industrial waste or raw sewage into a river. Thus pollution frames the discussion in misleading terms. In his article, he evokes early-19th-century London, where people made do, he says, “as they always had, with candles and rushlights and torches and lanterns” (with no mention of Jack the Ripper — 1888). But refer to Wolfgang Schivelbusch’s book Disenchanted Night: The Industrialization of Light in the 19th Century to discern the original motives for public lighting — ease of nighttime travel for those without a carriage and horses, reduction of crime and even more subversively, the start of social control in the public realm. These are the complexity of issues at hand when we discuss urban lighting.

I am not “for” light pollution — nobody is. I am for good lighting: illumination that serves a purpose, in the sense of safety (I can identify the mugger or rapist walking toward me), tasks (reading maps on a city street), identification (am I in Times Square?), and illumination that enhances our city nightlife for the greater good. In this case, it means helping small businesses attract foot traffic, cheering up long stretches of badly designed or neglected streetscapes for nighttime strolling, creating enclaves for social space at night — plazas, pocket parks — and ameliorating the visual environment where infrastructural forms like ramps, highways and vacant spaces cut across our cities.

I am against glare, pointless commercial lighting, badly conceptualized lighting and needless light trespass. If sky-glow is reduced, lighting designers will have all the more incentive to create beautiful light environments in cities with an ideal, darker backdrop of the night. For example, our lighting design for a large park on the outskirts of Shanghai designates swathes of darkness for nocturnal wildlife purposes.

1. Are the changes that need to be made to lighting design and equipment indeed simple?

Let us set the stage for this question, which is situational. The exurban and suburban contexts must be distinguished from the urban and roadway environment.

Exurban/suburban problem: My neighbor’s floodlight is aimed across my property line, or their ornamental maple is up-lit. Solution: Focus the light onto the driveway; turn off the up-light two to three hours after sunset and voilà — light pollution on a small scale is averted!

Does a stretch of street lined with lantern post-tops really cause light pollution? How do we reconcile our love of the gas lantern with our desire to reduce sky-glow? The charm of the authentic lantern form, depending on its design, resides in the visible light element (mantle or flame) or the glow of the translucent glass. What to do about the instinctual joyful human response to sparkle — generally caused by decorative post-tops, string lights and other unshielded fixture tops? Should there be a blanket ban on all up-lighting, even though illuminated large-canopy trees, with their branches and colorful leaves, create a romantic landscape loved by many? And what of innovative applications of light, such as the 9/11 Tribute in Light memorial — up-lighting at its most extreme, which in principle could be disallowed by light-pollution ordinances?

I know of no lighting codes that would ever restrict “public monument” lighting. In fact, the 9/11 memorial light piers are voluntarily restricted to a specific time frame due to the problems associated with “up” lighting of that magnitude. Lighting codes will require commercial searchlights to receive a permit from a governing board.

In the case of urban lighting, I believe that a consensus is not yet achieved, although the yearning for energy savings — and to help to save the planet — is. There are very exciting developments in the arena of electronic control for city lighting. These technologies will allow us to dim and turn off the essential publicly provided lighting in the future on a district-by-district basis. I believe that satisfactory solutions will be created with the involvement of local communities and designers. However, there are obstacles: For cities that rely upon existing locations for streetlights (for economic reasons) full cut-off optics are not always a valid solution. Physical, political and economic constraints make change difficult. And, questions of light pollution aside, the differing subjective values of a large metropolitan city with regard to its visual appearance is also a factor.

Easy prescriptions are not always correct, and comprehensive solutions are never simple. Ultimately, there is more to light pollution than light… a complex of social and economic factors as well as those of the built environment (design and architecture) also define the solution.

2. Is there any kind of consensus as to which lighting practices constitute pollution and which are essential?

There is no consensus. I have not yet seen the scientific response to, let’s say, the measure of pollution from up-lights versus bright surface lighting (roadways), facade lighting or high-masts — these are the current culprits we focus on.

Visit a city such as Las Vegas, New York’s Times Square…or Shanghai. In these places, spectacle is the norm for local character and identity, and although Las Vegas is located in a beautiful desert with an awesome view of the dark and starlit sky, the value of the commercial beacon has trumped the value of stargazing. Rural populations tend to agree on the privacy of property lines. Metropolitan populations range from “24/7” lifestyles where “the city never sleeps” to those living a balanced life, respecting circadian rhythms, in a city environment. Additionally, the “third shift” workers in large cities (transit, shipping, cleaners) have particular nighttime needs. And speaking of class, is there a single citizen living in a blighted neighborhood who would prefer less light? Is there a cop or first responder in a densely packed modern city who would call for reduced light levels in deference to the darkened night sky?

A number of thoughts and questions came up while reading your responses.
Both of you seem to agree that there is a difference between urban lighting practices and suburban/rural practices. Susan, I thought it was interesting that you believe lighting design in New York City is often more enlightened (so to speak) than lighting design in outlying areas. Does that mean there is less need for regulation in New York and other urban areas?

Quite the contrary: New York needs regulations to assure quality lighting. I was only saying that there are “good” lighting designs in the city because of access to expert lighting designers. Most communities do not have this resource, and the local architects and electricians are not trained in outdoor lighting. Regulations in those towns will outline criteria so that good lighting can be achieved for most utilitarian projects (e.g., parking lots and doorways) without a design expert. We have been using “Guidelines for Good Exterior Lighting Plans” here in East Hampton for years, and the results are terrific. The architects work with lighting manufacturers, giving them the criteria, and good plans can be achieved. Manufacturers will provide free lighting plans.

Please note here, the important international lighting designer associations IALD and PLDA specifically cite the practice of manufacturers’ providing free lighting plans as detrimental to the profession — in fact lighting designers employed by manufacturers may not join these organizations (they can, however, join IES [Illuminating Engineering Society]).

The practice of manufacturers supplying free design services is quite controversial. The plan may be free, but the fixtures are from a single source — that manufacturer’s. In essence, the lighting plan is a potent sales tool and at the same time undercuts the professional lighting designer.

While there are great differences between “urban” and “rural” environments, a person still needs the same amount of light to see objects/walkways, etc. And our cities are full of trees (negatively affected by all night lighting) and birds (traveling through on migration routes) that can benefit by better lighting practices.

Cities may choose to light more elements of architecture than rural areas, and to leave more lights “on” in cities that are active 24 hours. But “the city that never sleeps” actually is a city full of people who do want to sleep at night, and in their apartments without light intrusion, if possible. Even our bridge lights (decorative “necklace” lights) are shut off in the middle of the night. I can see the full spans of the Verrazano, Williamsburg, Manhattan and Brooklyn bridges from my apartment on the East River in Brooklyn, as well as the tops of most of the architecturally significant skyscrapers. I appreciate seeing the bridges and buildings lit, but I understand that it’s important to seek balance. They should also be lit properly.

Leni, highway and main-street lighting may be essential for reasons of safety and pure functionality. But you suggest that much urban lighting is essential in a different way: light becomes an architectural element, a landmark and a component of a city's commercial well being. Do proposed regulatory mechanisms take urban lighting needs into account? Should cities be regulated differently?

Interestingly, roadway (read “highway”) lighting is the generator of street lighting (as in city and “streetscape”) standards. There is a spirited discussion going on about whether the IES should have a separate committee for urban lighting; it does not presently. I am skirting the issue of regulation somewhat — standards are different from regulations — because I really do not believe there should be regulations, but a high level of motivation for implementing standards. Standards can change more easily than regulations, and it seems that standards may be more research-based than regulations, which I think (really, I am going out on a limb here) are more politically based and possibly influenced by the market. Certainly, if we have to have regulations, they should be very locally based and have change options built in.

I have found that municipalities generally adopt “standards” or “policies” with regard to their own practices. Laws are enacted to regulate private development so that building departments can require certain community standards prior to construction, and so that the municipality would have legal recourse to enforce the regulations. The only reason that a municipal council would enact laws for themselves is if they cannot change the standards otherwise.

Posted in: Health + Safety, Politics, Science , Social Good

Comments [17]

thought proving read! although i am in the design industry, never gave much thought to lighting designs. thanks for the article!
Ashely Adams : Sticker Printing

Thanks very much for opening the discussion on the issue of light in the dark. There is no discription of what lightpollution is and it may be different for various people. As a lighting designer you are always trapped by the questions that your employer asks, aside of course from your own responsibility by knowledge.
Henk van der Geest

Look Outwards instead of focusing on keeping all the light from reaching beyond our domain.

Maybe there are watchers who like the view of a star on a black ocean.

Imagine the disservice to those if we kept it all to ourselves.

Imagine if all the other stars decided to do likewise.

The sky would die dont ya think ?

"Dark Sky Activist" ??????

Shame on you,think of others,think out of the box,well,just think !!!!

Thank you very much for providing an interesting article on the issue of light in the dark.The pictures in this article are amazing.

Good discussion I support Leni wholeheartedly in her approach and I support the principle of "dark skies" and do my best in my work to achieve the best compromise between visibility and light scatter. There are a couple of major points that need to be addressed. Over the course of the last century as lighting technology improved more and more light was expected and required in lighting codes and by users. A battle of brightness if you like, as retail window lighting got brighter public lighting had to get brighter for it to retain effectiveness by maintaining lighting within an acceptable contrast range. In the one or two centuries since we have had mass artificial light our visual systems have not evolved to any significant extent so we do not need as much light as we are now getting for the majority of outside tasks. Next time you get into the countryside at night switch off your torch and give your eyes time to adapt to the natural star and moonlight, mostly you will be able to navigate by this minimal amount of light. Look at the standards for emergency lighting. The average illuminances are very low yet we are expected to navigate our way through unfamiliar corridors and stairs by this light. The bottom line is we need to significantly reduce all illuminances in the nightscape.

Whenever we see images of the world at night or experience sky glow it is almost always the sodium orange of street lighting. Why do the dark sky campaigners want to restrict lighting of buildings and trees when this bigger issue is not solved? Street and roadway lighting is expected to have a very long life and is generally public funded by city or state taxes so it is not an easy target. Roadway lighting needs serious reconsideration. We need to enforce the adoption of high cut off luminaires, review and research the habitual approach of lighting the road surface as the best way of providing visibility of objects, reconsider the light levels required and re-think how lighting levels are controlled in response to traffic, basically lights need to switch off when there is no or little traffic. We have new technologies including but not limited to the heavily promoted LED that provide light much more responsively to controls so we can do these things but have to review the current somewhat simple minded thinking on roadway lighting to build up new recommendations that reduce light levels, mandate intelligent control and operation and set faster timescales to get rid of old systems and equipment.

Kevan Shaw, Director of Sustainability for the Professional Lighting Designer's Association

Kevan Shaw

Kevan, Thanks for your thoughtful comments. These issues really are so complex, I hope that many lighting designers will weigh in like you have. -- Leni
Leni Schwendinger

Thanks for this really interesting article. Lighting pollution is, indeed, a big issue. Once I was coming back from the US, arriving in the early morning time in Amsterdam, I could spot hundreds of glass houses, illuminated extensively to raise plants. Even though it looked quite funny, seeing all those lightpoints shining through the clouds, it also made me aware on the amounts of light which we send into space. I was alerted and more sensitive since then and I also could see this light pollution in my neighborhoud.
I worked a lot for TV in the past. We are able today to create dimensions within a show setup, which are made by light and shadow. But in architectural lighting, we commonly overdose lighting and correct it by using dimmers. Nowadays, I really pay attention on the use of light and how much is really necessary. Using LEDs, for example, can be a good alternative, not always, but it allows us to reduce energy consumption and helps to create a relatively green environment. But only as long as we don't follow the same way of using light in extensive amounts. In my opinion, illuminating with more sense for the real need, combined with latest technologies, will be a significant step towards a more interesting (in the design point of view) and much more economic new world.
I heard about a town in germany, where you can switch on the street light in front of your house for 15 minutes by sending a SMS to a related number. Otherwise it will be switched off at 9pm. This gives us much to think about - not only about the sources of light, but also on the way to control them.
Yes, i do enjoy this discussion and I will appreciate every reply.
Greetings - Detlef

Detlef - thanks for posting your observations. Lighting controls will be instrumental in future creative public lighting and energy saving programs. What did you think of my idea for a Citizen Advisory Lighting Corps in every community district to create guidelines for the controls? (Approximately paragraph 24 in Part II

Yours truly,


Leni Schwendinger

Interesting discussion!
In the Netherlands a few main cities already introduced dimmable public lighting (with Dynadimmer or digitally controlled internal/external). Of course we have our regulations, on crossings the lights will not be dimmed, but a standard road can be dimmed to 50-60% and the people didn't even noticed it. Surprisingly good results on energy saving and also the light source has a longer lifetime. As far as I know: until now no results are available for publication. Naturally all new installed fixtures do have at least full cut-off specs, but not in the heart of old cities, with traditional cast iron poles and fixtures it is just creating the right anbiance by using no full cut-off fixtures.
Here almost each city-board already wants to create a maximum "green environment", so all public lights should be "functional": e.g. a simple flood light on a bridge must exact lighten the details, each degree light what creates shadow or only the sky, must be blended/dimmed/cut-off. Perfect for that use are leds, although they are not so system/energy-effective as e.g. CPO-TW dimmable lightsources.
Status september 2009 in the Netherlands: our country government preaches a maximum green environment, by using e.g. sustainable lights (what ever that/they may be...) and so each local city-government is in the race for having with the best sustainable lightsystems. Everyone installs in new projects new full cut-off fixtures, invests in leds systems and lightpolution is then a naturally no go area, so no regulations for light polution are needed!
Marten Hilbrands

I think both the writers have interesting points, but I think we also need to come back to the full implications of the original question - how simple is it to cut out spill light? The truth is that roadway lighting is relatively simply controlled to be 180 degree cut-off, that is to say, no direct light above the horizon. Does that help? Sure, of course it does. Does it solve the problem? Not at all.

As long as codes require minimum light levels on the horizontal surface of the road, and as long as the lights are turned on, the light reflects, in part, into the sky. As such, we, and the Dark Sky Society, need to accept that in the urban context of cities with 20-50% of their area devoted to automotive transport will never be dark. So, should we make these areas open-season territory for all lighting? Well, at the literal interpretation, no. There is no excuse for unnecessary lighting, and light lost in the sky is generally just that. That argument really comes down to an energy efficiency question. But at a more generic level, yes, perhaps we need to step back from light pollution guidelines (LEED, etc) when we're in a dense urban center. Maybe we need to say "hey, we'll never win here, so let's make this a rich urban design environment."

What about in the countryside? Here we should be more serious about cutting out excessive light. Here we have genuine control. Dusk-til-dawns, and yard lights without shields and motion sensors? Unacceptable. Uplighting trees? Only between certain hours. Roadways? That's what headlights are for.

All parties need to differentiate between these environments and tackle them in different ways. We need to accept that security, economic activity and quality of light are at stake as well as pollution and climate change questions. We need to get sensible about this and come up with context based strategies.

Thomas Paterson

As always, I'm impressed with the Dutch approach. Marten Hilbrands writes above:

"...so each local city-government is in the race for having with the best sustainable lightsystems. Everyone installs in new projects new full cut-off fixtures, invests in leds systems and lightpolution is then a naturally no go area, so no regulations for light polution are needed!"

Like, if you live in a country where you can achieve consensus on an issue like light pollution (or anything, for that matter) you don't need a regulatory framework, only a well understood goal. Then creativity does the rest.

Karrie Jacobs

Dear Leni,

sorry for my late reply but there was no chance to follow up in time. You mentioned the idea of CALC....interesting. Yes, I like this thought, it combines some very important subjects:

1) Education about lighting
Certainly the necessary first step to enter a project like this. I disagree on regulating everything by a governing agency but absolutely fancy the idea of educating people to take care within their own responsibilities. Lighting is having a lot of impact on how people feel, therfore I believe overall laws will not be the right tool to be applied here.

2) Involment of people from the community.
This is not just a practical but also a socially highly interesting subject. Educating and involving people from the community will positively reflect their responsibilities inside of the community. And since this would not only concern the reduction of light for the good reasons you already mentioned but also most likely lead towards a more sensitive use of energy in general. I believe that this is also very important.

I have read a couple of interesting ideas and opinions here and I am highly interested in this following this discussion further.

You have some very good points here and it is certainly worth to continue this discussion. I personally also like the idea of interactivity in lighting. We are living in a digital world, why not use the possibilities it gives us? I am looking forward to any response and hope my comments can be somehow useful for you.

Many greetings

Welcome all to the world of responsible outdoor lighting. I am a manufacturers rep in Tucson Arizona and we have been working on the protection of the dark skys of Southern Arizona since the late 1970's. Tucson is surrounding by mountain top observatories and their ability to see into deep space is the emphasis of our ever changing Outdoor Lighting Ordinance.

The Tucson and Pima County lighting ordinances are two very well thought out documents that work well for our community. Although they are restrictive the closer they get to the observatories our design community is able to work within the guidlines of the ordinances in almost every design.

Why waste light? Why not just put it where it's needed? Granted there are many urban areas that benefit from lighting facades and uplighting trees, yet there is that ability to light from above. Not all communities need to have as stringent lighting codes as we have here, but there is no reason not to have responsible design and installed fixtures.

Over the last 15 years the availability of full cutoff fixtures has gone from the lowly old shoebox to hundreds of different visual offerings. Although reflector design is much different from manufacturer to manufacturer most of them have a wide variety of shielded fixtures from which to chose. Good lighting is more expensive than bad lighting initially, but over time a lower lumen lamp choice with a quality reflector will save dollars.

The IDA, with its beginnings in Tucson, has blossomed their concept of Dark Skys throughout many communities of America and beyond. Lighting art and architecture does not have to be a full nightime job. New controls systems help to limit the use of all-night lighting when unnessesary. Just a matter of responsible design and installation.

It will be interesting to see what the future holds for LED oudoor lighting and information that will be provided by IDA and others in the lighting community about the spectral analysis of LEDs. At this point not much has been mentioned about the useful(to human vision) and non used spectrums of light emmitted from LEDs.

If you want to see a good use of outdoor lighting take a flight over Tucson and see what's been done for the last 30 years. Please remember there was a lot of grandfathered unshielded fixtures before 1980.

Thanks for letting me chime in.
Craig Barron

A lot of people have this flair for doing some of the most creative things under the sun. Well, if you don’t like to study and are more inclined towards the creative arts, why not get going with some of the creative job alternatives around. You can be an advertiser or artist, but your work will be to innovate on a diversity of areas, thus providing the world with new products and ideas. It is often a tough task to find a niche in the creative fields and build a career out it, although a lot of creative individuals devote their lives to creative jobs. The arena of the creative jobs is ever expanding so much so that today people and individuals with a degree not just in the arts, but also in the sciences can gain relevant jobs in the field. This is true for interior design careers and fashion jobs.
Michael Fish

The topic discussion sheds light on controversial issues facing Dark Sky regulation which inadvertently benefits the hard core activists as well as its initial objective – to protect and enrich the health and quality of life of the city dweller. Lighting designers should act responsibly and strike a balance between the project architects requirements and that of the surrounding elements in proposing sound practical lighting solutions in keeping with technology and the times.

Arjun L. Gunawardene, proponent on sustainability in design.

Arjun L. Gunawardene

Mmmhh... Right... Surely the idea must first and foremost be to educate people. By enlightening people and getting them involved the results should be obvious. Reductions and a more responsible way of dealing with energy in general. The author mentionedLighting in Las Vegas and the waste here is just immense. Surely legislation should be put in place in order to avoid that we cities with that level of consumption.

However, this is just one of many issues that should be tackled.

Thank you for a good post.

Best Wishes,


I actually hate the artificial light skylines. I would much rather see a beautiful sunset over the ocean than the lights of Las Vegas. The amount of light pollution means that none of the stars are visible and the bright neons give me a headache! That said, I have used Coupon Code Scout in the past to find lighting stores that offer natural looking lighting for my home. I usually go for energy saving bulbs as they are less harmful to the environment but also, much easier on the eye!
Daniel Sayer

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