I've been watching some of the neighborhoods undergo early adoption of LED street lamps. It's been interesting.
The new lamps are definitely much bluer than the current sodium lights, which gives the street a different, unfamiliar feel. The article suggests the city ultimately adopted 3000K lamps, but it definitely feels like the pilot program used 4000K ones, they looked very cool.
Another interesting development with these so-called "smart lights" [1] is that the city can potentially modulate brightness on a street-by-street basis, and asking different neighborhoods to weigh in on where they want the lamps to be brighter (or maybe, if they want them dimmer on side streets etc). This sounds like a very good change - customizing street lights based on neighborhood requirements is a very nice development!
All color considerations aside, one thing I find quit discomforting (first subconsciously, until I put my finger on it, and now even worse) is that led lights are very very often a rectangular array of lighting elements. So instead of a point (or at least a large diffuse, continuous "point" in various bulb constructions) there are between 25-64 points of light in a 6"x6" area. From a 20' light pole, looking at the shadow of your hand on the sidewalk, you see (let's say) 36 different vague shadows, in a rectangular array, with a disfigured hand shaped, darkest shadow in the middle where the shadows all overlap. Truly, it can be dizzying if you try to focus on the shape of the shadow from a single object. Tree canopies become shifting fields, everything gets a blocky 16bit feel to it. I'm only human, but I can imagine some animals are well tuned to single point shadows and this effect might really throw them off.
(Interesting aside, I first noticed this while leaving LACMA (LA County Museum of Art) where the pure Instagram gold of Chris Burden's collection of old LA street lamps tightly packed, produces the same effect)
Does it differ too much from vague shadows on an overcast day? I'd say 64 close-by shadows look more natural than more distinct 4, which I could clearly see with regular point-source lamps on tall poles.
But AFAIK LED brightness is usually controlled by pulse-width modulation, which is essentially adding flicker.
There are people with flicker sensitivity that have headaches when exposed to flickering light. A link to a HN discussion that touched the problem of PWM and flicker in the comments: https://news.ycombinator.com/item?id=13330611
In my subdivision in a metro Atlanta county I the local power cooperative is replacing failed halogen/sodium/etc street lamps with LED.
The orange lights provided good light but the same pole with a LED now lights up the area as if it were full moon or close to it. You cannot look directly at these lights where you could at the older lights. I have an orange lamp in the corner of my lot but the nearest LED is about three hundred feet away and it still puts out more.
One oddity which I cannot completely attribute to the lights. Birds in our holly bushes were singing at very odd hours for the first weeks or two but have apparently moved to bushes and trees in the back yard.
I wonder what the effects on other animals will be. Maybe this is the thing thats killing the honeybees.
Ok probably not, but if humans can be out of whack from this, I wonder what other creatures will start to lose sleep - or will nocturnal animals sleep in all night?
Yea I live on a street with the pilot program and no doubt they were much brighter than 3000K. They were very blue but I really like them. It gave my neighborhood a more small town feel if that makes any sense.
I always perceive blue light as brighter. I dabble in indoor lighting, and warmer (bluer) bulbs always seem brighter. Unless the brightness of fluorescents changes with the color temperature, I'm inclined to agree with the original comment. Besides, nit picking is rarely useful.
There's actually a reason for that - bluer light reflects in front of the retina rather than focusing onto it, and so it scatters throughout the eye more than other wavelengths, especially when there's little ambient light. It's called the Purkinje effect.
The light doesn't have greater luminosity, but it is perceived as brighter.
We are all just trying to help someone be more correct. For me at least, it isn't because I wish to nit pick. Perhaps you could have had a more useful comment by not adding your personal anecdote and instead providing a citation?
The other responder to your comment is correct. It is entirely perceived and there is no real change in luminosity and thus brightness is the incorrect term.
I was offering my insight as both a graphic designer and amateur technical 3D artist with solid grasp of color theory and optics. Meanwhile you just butted in to tell me I'm wrong and I shouldn't tell other people they are wrong.
That's a conflicting position, and furthermore the person I was replying to was correcting someone else, and I was clarifying for both of them. So I really don't know why you felt the need to comment in the first place.
Either you're responding to the wrong person, or you did a very poor job at reading my comment. In case of the latter:
> Who is nitpicking here?
You and /u/colechristensen
> We are all just trying to help someone be more correct.
No one doubts the purity of your motives.
> The other responder to your comment is correct. It is entirely perceived and there is no real change in luminosity and thus brightness is the incorrect term.
No one disputes that the effect is perceived.
> I was offering my insight as both a graphic designer and amateur technical 3D artist with solid grasp of color theory and optics.
No one disputes your qualifications.
> Meanwhile you just butted in to tell me I'm wrong and I shouldn't tell other people they are wrong.
No one said you were wrong. I simply said that my experience is like that of /u/icelander and /u/pducks32 in that I perceive blue light to be brighter, which you disagreed with in your previous comment, but seem to agree with in this one. I didn't tell you not to correct other people, I said nit picking (i.e., correcting a minor discrepancy which isn't important, relevant, or otherwise causing confusion) is rarely helpful.
Interestingly, /u/Karunamon pointed us to the [Purkinje Effect][1] as an explanation for why blue light is perceived to be brighter, so perhaps you aren't correct despite your qualifications (I guess you espoused both sides of the argument, which would make you simultaneously correct and incorrect :p ). This certainly isn't my subject, so I'll leave you to sort it out on your own.
Our sensitivity to light has no bearing on how bright it actually is.
You're going to great lengths to nitpick yourself, my friend. This is downright silly so I think I'm done. You're arguing just to argue. Feel free to have the last word.
The difference on the ground is quite noticeable, partly because we're so used to sodium yellow and as LEDs are in the 6000K range - i.e. daylight ... it's 'uncanny', things certainly seem more HD - here's a picture I recently took at night:
This is where smart lightbulbs - like the Hue - are great. The allow to tune the color temperature and the brightness according to the situation. In my bathroom at night, the light comes on only to 50% and at a much warmer tone. For my living room, I have a pure dark red setting, whenever I plan to do some stargazing.
I have migraines and I use Hue to control temperature. I find the cooler the light (blue, white) the easier it is on my headaches, where the warmer (yellow, orange) light makes me feel like I'm squinting, or in a daze and not fully awake. With Hue I can change just the area of the house I'm in to cool white and my wife can have her yellow warm glow everywhere else.
The white LEDs make me think of housing projects since they often have brighter non-sodium flood lights (to deter mischief ), in contrast to the next block over which would have sodium.
What I wonder is: ok, so LED ligts save a lot of energy, which is great. But do they all have to be #FFFFFF white? Given that there's LEDs in all colours, would it be much more expensive to build/ buy/ run e.g. orange LEDs?
That's a general problem with efficiency regulations: they don't model the full benefits of the (product with) higher energy use, nor do they give the users a chance to pay for the purported externalities if they they value them so highly.
In that respect, they commit the planner's fallacy of acting on costs they can't observe.
(If your model says that the externalities are infinitely bad and inherently unaffordable you're probably very wrong.)
The solution would be a simple carbon tax rather than efficiency thresholds. I don't understand why the supposed "small government" folks dislike a carbon tax when it'd avoid so much bureaucracy.
It's about pricing back in what is now externality. It's about making things fair. Which is the basis of living in a society. For max freedom, people should move to Somalia.
What makes you think you can achieve maximal freedom without a functioning Government to enforce the rule of law? I think you're erecting and attacking a strawman, there.
Well, yes. Everything from murder to moral, legal police action can be so described.
> It's just a law that some people don't like.
... because it's legalised theft.
Libertarians (well, minarchist-Libertarians) support Government, and the rule of law. That doesn't mean we support _all_ Governments, or _all_ laws, as moral.
One of the main attributes of the state is its ability to tax things. You cannot have one without the other. If the bad thing is the tax just for being a tax, then it is legitimate to compare against a no-state situation.
Modern white LEDs are actually a blue LED behind a yellow phosphor mask that turns the light white. More power emmited in the blue side of the spectrum results in better efficiency, and the difference is significant.
The “better efficiency” of privileging the blue light coming directly from the diode is oversold.
At night, what happens is that directly visible blue lamps in your peripheral vision cause a severe adaptation response from your eyes (a kind of “oh hey, it’s daytime” misjudgement), which causes everything that isn’t directly lit to recede into dark shadow as the rods are swamped. You end up using mostly cone vision, where the blue part of the spectrum doesn’t really contribute to brightness response anyway, defeating the original purpose.
Longer wavelengths don’t cause the same kind of adaptation, allowing the rod cells in the eye to remain useful down to much lower levels of overall environmental lighting.
Industry has made up bogus metrics/arguments about “mesopic efficiency” of high-CCT street lamps and car headlamps which are IMO based more on marketing needs than dispassionate scientific investigation.
I’m hoping that someday non-industry-funded color scientists will do some proper research on the glare and adaptation effects of different outdoor lighting sources.
You may have solved an issue with a new tunnel here in the Netherlands. The contractors and operators are puzzled why the accident rate of the new tunnel is so much higher than the old one, what with all the efficient and 'bright as day' white light. But if you're right and that adaptation happens then likely going into the tunnel your nightvision gets 'switched off' long before you still need at (at the tunnel entrance) because you're staring into the well lit tunnel, and at the end of the tunnel your eyes are likely still overloaded and are re-adapting to darkness.
The monchromatic lights they were using before probably did not cause any such adaptation and therefore did not mess up the nightvision of the drivers to the same extent.
They have tried to remedy the problem by dimming the lights overall and gradually upping the intensity as you get further into the tunnel but it is still a problem.
So do I understand you right that would mean that during the night they should use monochromatic lights and during the day white?
Edit: I've sent an email to 'rijkswaterstaat', the federal infrastructure department of the government here with a link to this thread. Let's see if they reply.
What they should probably be using is a lower color temperature, and likely a lower intensity. Light with a lower color temperature has the majority of its energy in the red/yellow end of the spectrum, and that has a lesser impact on night vision.
I see the article says the intend to dim the lights, which is probably the most important factor.
When Caltrans rerouted the Bay Bridge here in SF, they also took the opportunity to clean the central tunnel through Yerba Buena and replace its lights with similar "bright as day" lighting. At night, I notice I unintentionally squint as I enter the now blindingly-white westbound tunnel, and my eyes feel "disoriented" (for lack of a better word) when I come out.
I thought I'd get used to it by now, but I haven't. Maybe similar.
I've taken to putting on sunglasses when I drive through that tunnel. Yes, even at 11pm, which is when I usually find myself going through it. I think I might be more sensitive to light color and brightness than most people.
I could be wrong but it seems to me that the near-unreadability of blue commercial signage at night is probably another aspect of this whole category of concerns.
It depends whether you're myopic or the opposite. Things are blurred for me (myopia) on the red side of the spectrum, but blue is sharp; Other people have sharp reds and blurred blues.
Well, many transport authorities don't care and would rather save money on electricity costs and materials (less LEDs and less powerful drivers) than actually make the road more driveable at night.
They would save even more money on electricity by just cutting the brightness of the lamps. Whatever official body or industry recommendation sets the standards for urban illumination really needs to bring things down.
My street’s new LED lamps could have their intensity chopped by 2/3 without adversely affecting anyone’s vision.
The electorate believes that brighter street lighting leads to less crime, and dimmer street lighting leads to more crime. A municipal politician's career would be eviscerated by the first violent crime on a street they voted to dim.
"Soft on light pollution" doesn't kill political careers.
Well, they might even be right. See, if the electorate believes it then likely so do the muggers (them being part of the electorate). And so the muggers will seek out the streets with the dimmer light.
Even if the science is lousy it might actually work out that way if there are streets with and streets without dimmed lights.
So the only way to control for this is to have the whole city dim the lights on some nights and not on others to compare when there was the most criminal activity.
Another way to control for it is to increase or decrease lighting in some locations while leaving others the same and see what changes occur to crime rates. That has been done at least once, in Chicago where low-output lights were replaced with much brighter lights in some alleys but not others, with controls for various demographic factors and prior crime rates.
The result was that crime increased where brighter lighting was used. One plausible explanation is that committing crimes, like most human activities is easier when there's sufficient light to see what you're doing, and using a flashlight is a poor option when you want to avoid calling attention to your illegal behavior.
That's only true for victimless crimes, and the bulk of the increase in non-index crimes in the study was drug-related. The study mentions increased reporting due to visibility as an explanation.
The index crimes increased as well. Those include homicide, assault, burglary and theft, all of which have victims.
I'm not sure why you're getting downvoted (lack of a citation?) but I think you're right. To the extent that most people think about this at all I bet they would say they prefer bright street lights to dimmer ones in their neighborhood.
Thank you. You've confirmed a long-standing suspicion regarding how white LED lamps are actually worse than yellow sodium for streetlights and headlights.
He had a suspicion, but no logical reasoning, until one was offered here on HN. That logical reasoning seemed rational and persuasive so he chooses to believe it.
Your snark is awfully unwarranted and entirely unwelcome.
The effect would have to be stronger than the differences in luminous efficacy to work, which is about 10% between 3000K and 4000K. This is a great theory, but you provide no supporting evidence. The "bogus" metrics you complain about are based around real color research done in 1931, far before people were marketing LEDs: https://en.wikipedia.org/wiki/Luminous_flux
No, I’m talking about stuff like https://scholar.google.com/scholar?q=mesopic+efficiency (add keywords about street lamps and car headlamps if you want more recent and specific results). The relevant literature is mostly from the past few decades, and ongoing.
Luminous efficiency is not the only thing we should care about here. What we want is for the road and objects on it to be clearly visible to someone with dark-adapted vision, and for individual sources of light to be visible but not cause glare or distraction. Obviously a brighter light does a better job of making itself visible and illuminating things directly in its path; the problem is that brighter lights which are intense in the blue part of the spectrum cause more glare and more adaptation than dimmer yellower lights, which makes everything that isn’t being directly lit by them effectively less visible. If objects directly under the sweep of car headlamps are lit to the same extent as during a sunny day, then the shadowy bushes off to the side of the road and the kid running out from behind them are going to be very dark by comparison.
I’m not an expert in this specific topic (I’ve studied much more about color vision under well lit conditions), but several of the papers I skimmed when I started looking into it because I was frustrated about my street’s new LED lamps seemed to be funded by industry, and I’m not convinced that their experiments mirror real-world conditions of nighttime streets, or properly measure the effects of adaptation and glare.
The lighting industry wants to use a measure of luminous power based on “mesopic conditions” (i.e. mix of photopic + scotopic) because if they use the photopic function then blue light doesn’t really contribute much and their lamps don’t look as efficient or bright. My personal experience is that bright sources of blue light in my peripheral vision cause enough adaptation that I’m not convinced that a “mesopic” function as they’re using it is actually appropriate.
I should probably email some real color scientists to ask for clarification someday. If you know of a nice survey paper written by someone with industry-independent bona fides, I’d love to skim it.
There is value to having things look like the colour they actually are outside of photography. Think of the nice red dress turning brown in the article.
Mixing colors in the array would be horrific. The array is sparse enough that each LED casts a distinct shadow through foliage. This forms a unique lighting texture on the pavement. If each LED were randomly red, amber, green, you'd have wild colors all over the pavement.
Single color is the way to go. And the broad spectrum produced by phosphor makes for better vision compared to the narrow spectrum of sodium or straight-LED lighting. IMO the best option would be phosphor + yellow or green LED.
It's pretty much a set pattern through the whole electromagnetic spectrum:
The longer the wavelength, the easier it is for manmade artifacts to produce it. All the way from AM radio to X rays.
The shorter the wavelength, the harder the tradeoff between the expense of manufacturing the device and the cost of energy to use it.
That's why if you were tinkering with electronics in the 90's, you watched how LED makers started with red, then made green ones, and what a big deal it was when the first blues came out. They were faint, and expensive. It took some time for them to become practical.
I remember reading how rare and expensive blue LEDs were, then found one being used for the high-beam indicator in my 1985 Volkswagen. Made me wonder what all the fuss was about.
It still doesn't answer my question about efficiency.
These two sentences contradict each other. It's good for nighttime to be dark. Berlin sounds quite appealing as compared to other cities, in this respect.
Why not replace the transparent cover with a different color? Or glue a sheet of plastic over the LEDs in the exact tone you want?
From what I've read, orange LEDs are generally more expensive in and of themselves. And to order them for streetlights when everybody else is using white would probably be 4 or 5x more expensive.
As all these cities convert to LED, not a single one is remembering one of the big advantages of sodium lights on the environment -- it's better for the animals. A lot of animals navigate by moonlight. When it looks like there is a moon every 50 ft, that really screws them up.
Not to mention how bad it is for humans. I installed a bunch of 1850K lights in my house as well as f.lux on my computer and night watch on my phone. After 11pm, I try to avoid any light above 1850K at all costs.
And it has worked. I sleep a lot better since I went "all 1850". But when I have to drive late at night, it screws that all up.
Many neighbourhoods did not convert to sodium lights until the 70s and 80s.
For the better part of the 20th century we used mercury-vapor street lights, which bathed the streets in soft blue light. The complete lack of red wavelengths in these lights would make a red car look black, and made humans look like vampires.
I use a Mac, in which Night Shift only works on the newest hardware apparently and besides, F.lux has more features. For example, even during the day I set it to 5800K, just to cut the harshest blues.
It wasn't easy. I actually ended up getting the GE "C" bulb, which is the one that you can control with bluetooth. At the lowest setting it goes to 1850K. The nice thing is that it can go up to like 6000K too, if you want that.
As you can see from such a search, there are a huge variety of said lights. I asked so that I'd get feedback on a known-good source/brand. Do you have any suggestions?
Current versions of LED streetlamps are absolutely awful. They have very high blue glare which is not only momentarily distracting in peripheral vision and disruptive of sleep cycles but also totally wrecks your night vision. It doesn’t help that they are often turned up to several times brighter than necessary. Same goes for LED car headlamps (especially on SUVs), which should be regulated right off the road. After San Francisco installed some awful LED lamps on my street, I’ve taken to wearing orange safety glasses when I walk my dog, and if I had to drive with any regularity I would consider wearing orange glasses to drive at night.
The excuse I’ve heard that “these are the same color as moonlight” is total nonsense. We don’t have 10 moons hanging 20 feet off the ground on every city block. Nighttime is not supposed to look like daytime. People are not supposed to be reading novels in the street at night, or critically examining the colors of paintings.
Moreover, much of the efficiency story is exaggerated. Recent types of high-pressure sodium lamps are very efficient. The big advantage LEDs have is that they (theoretically) don’t need to be replaced as often. We’ll see how it goes in practice over the coming decades.
The real story of course is that lighting companies have made a big marketing push, and from what I understand there is state/federal grant money available for new LED lighting projects (which are sold as “environmentally friendly”, etc.).
If cities want to use LED street lamps, they should be <3000K correlated color temperature, with as little blue light as possible. They should include diffusers, should be shielded to not shine in the eyes of pedestrians or drivers who aren’t intentionally looking upwards, should be spaced closely enough together that there isn’t a huge contrast between patches of dark and light going down the street, and should be set to a reasonable brightness. Human rod vision is incredibly adaptable to seeing in very dark situations.
>If cities want to use LED street lamps, they should be <3000K correlated color temperature, with as little blue light as possible.
Agreed that as "little blue as possible" is preferable, however, 1900K at high lumens should be the target, IMHO. Man is adapted to see at night via firelight and 1900K hits the mark.
Actually performed this experiment at home...
After having used clear bulbs for far too long, bought several of the following for our living room:
The "feel" of the room is entirely different, particularly when unwinding after work. "Cozy seat at the fireplace" best describes it. Our baby falls asleep gazing at the bare bulbs.
Conversely, for the locals loitering to rap in our alley, bought a "clear" 150w mercury vapor fixture and bulb from e-Bay. Installed the light and even the cockroaches no longer venture into that eerie glow. If the mercury vapor alone doesn't solve the loitering issue, one can purposely damage the fixture's transformer so it produces an intolerable buzz.
Perhaps the correct lighting depends on the situation.
For those not overjoyed at the idea of spending $22 per bulb, G7 Power makes [1] a low-color-temp bulb on an E12 base. I have several, in various accent lamps and nightlights, and they produce a pleasantly orange glow that's much warmer than the 2900K specification suggests.
> Current versions of LED streetlamps are absolutely awful.
Also they flicker too much -- a lot more than any other lighting source. It's utterly hateful and distracting, especially when you're driving or looking at a moving object.
They also fuck up dark adaptation, which makes people materially unsafe. I want the best possible night vision when I'm out alone at night -- to better be able to detect, avoid, or defend myself against any sort of miscreant that might be hiding to ambush me.
This is especially problematic because many of installations of outside lighting are done in order to provide better security, but if they're lights that dazzle and destroy dark adaptation -- this ends up being counterproductive.
I think if they're at the same frequency then they will appear to - the LED has a much sharper on/off curve than anything else. Certainly in one of the places I work they have new LED lights in the toilets and it's quite disconcerting as the strobing effect is noticeable.
The LED lighting in the streets in my town (Bournemouth, UK) doesn't exhibit this, but certainly is very 'blue' at first, and my mother (who lives there) didn't realise the effect of the blue light in terms of sleep; she used to leave her curtains open at night and wasn't sleeping well. Closing them has helped greatly in that respect.
Good fluorescent bulbs will have electronic ballasts (the driving circuit) that supply current to the bulb with a higher frequency (in the low kilohertz) than the time response of the bulb's phosphor. Thus, any sort of flicker gets low-pass filtered and doesn't appear in the output light.
Even with a subpar magnetic ballast that drives the bulb with line frequency, the phosphor never gets close to fully extinguishing -- so there is flicker, but the instantaneous light output never gets less than, say, half the maximum instantaneous light output. Look on page 3 of http://www.usailighting.com/stuff/contentmgr/files/1/e18f88d... for some instantaneous light vs time graphs for fluorescent bulbs.
LEDs have a much higher frequency response (in the tens of megahertz, easily) -- they respond quicker and more faithfully replicate their electrical drive signal as light output. You can see on page 4 of that report how violently jagged the LED's light/time plots can get.
If the manufacturer didn't want to include filter capacitors in the LED's driver because of cost/reliability concerns, well, I hope your eyes enjoy that signal because the LED, unlike the fluorescent bulb, isn't going to smooth it out.
It's certainly possible to do so and doing so would indeed avoid any sort of flicker -- but cost-cutting (good capacitors that will last the life of the LEDs are expensive) reigns supreme alas.
Blue spectrum's shorter wavelength makes it scatter readily and thus people experience glare and difficulty focusing on objects in blue much more than the red end of the spectrum. It's even worse in fog and rain.
> After San Francisco installed some awful LED lamps on my street, I’ve taken to wearing orange safety glasses when I walk my dog, and if I had to drive with any regularity I would consider wearing orange glasses to drive at night.
Thanks for the idea. I can't stand blue headlights, so I'm going to add orange safety goggles to my shopping list.
This is mentioned in the article: the new streetlights are going to be at 3000K, between the 2200K of the sodium lamps and the 4000K of normal LED streetlights. It looks pretty good to me.
3000K is still not great. I would prefer they cut the light from the blue diode entirely. But 3000K is much better than the 4000K version.
“Color rendering index” is an absurd standard for nighttime lighting. (Not to mention a hacky ad-hoc metric from a few decades ago which is pretty terrible for any purpose, but that’s another story.)
Someone should make a “night vision clobbering index” by which to judge the SPDs of outdoor lighting.
I remember when the sodium vapors started deploying. Ugh... a fairly common reaction, at the time.
So, this may be a "change." But it's a change away from a few decades of orange.
One thing I wonder, is whether they will continue to deliberately "light everything", or whether they will implement some tuning to restrict lightflow to more relevant areas.
It isn't just street lighting. In places like Chicago, they've chosen in many areas to make that light as much as possible a seamless and universal presence. It doesn't just illuminate the streets and walkways. (Because crime, is the primary rhetoric around this.)
P.S. One difference between the sodium vapor (and before them, the mercury vapor) lights and the new LED lighting, is that the former hang down within a diffuser. This makes it easy to have illumination up to the second story windows. The LED lights I've seen have the LED's within or at the edge of the overhead hood. I wonder whether such broad illumination is as readily achieved with them. Also, the LED's are very bright pinpoints of light. Especially if they are going to go for "illuminate everything," this could make looking down the street kind of uncomfortable. I, for one, do my best not to look at those bright spots -- they are painfully bright, and I even worry about vision damage.
a new building development put up LED lights and its awful. I cant open my curtains without having piercing white like come in. its hard to explain, its not like a spot light is on the window, but it hurts my eyes even when its hitting the peripherals.
I know what you mean. The words "sterile" or "clinical" come to mind. Chalk it up to another unintelligent fad, much like the 20,000-lumen tiny blue LED lights hardware manufacturers use indiscriminately as status indicators. Lord, I've wasted so much duct tape covering those things...
The apartments across from mine were renovated and the outdoor lights replaced with LEDs. Wrecked my sleep for months until I wised up and bought blackout curtains. Those things are truly awful.
Have a streetlight outside my house that has LEDs that are not diffused in any way. If they simply put a cover over it that diffused even just a little it wouldn't be so blinding.
San Jose also uses orange sodium lights to help reduce light polution for the Lick Observatory.
I agree with the article they have a "gloomy" effect. They are also pretty much the exact same color as the yellow in traffic signals, which can make driving at night a tad more annoying.
Light pollution is another important side aspect of this. What if, as light becomes cheaper, people/ cities just use more of it? From other comments, it sounds like this is already happening with LED.
LED will pretty much be better in terms of light pollution. With tubes or filaments, you need to make expensive reflectors to prevent the light going in directions you don't want.
LED lighting is much easier to make directional. With LED lighting, the difficulty is making it more isotropic.
Sodium lights are trivial to block using optical filters. This is very common in astronomy.
LEDs + phosphor, not so much, due to their wider spectrum. That less is emitted directly skyward doesn't help if what's reflected off pavement can't be filtered out. (Pavement is surprisingly reflective even though it's "black".)
The main issue I've heard about is that LEDs are generally more wide-spectrum than sodium vapor lamps. This leads to a lot more sky glow (light pollution). There's a good webpage about this here: http://www.flagstaffdarkskies.org/for-wonks/lamp-spectrum-li...
The'll probably want to switch to the LED lights then. They produce any light pollution compared to the orange sodium lights. The difference is quite startling.
Definitly not. Sodium lights obly emit a very narrow spectrum of light (esp. the kind used around observatories) which can be easily filtered without losing a lot of the availible light. LED + Phosphor emits a much wider spectrum.
I would definitely get tested for colour blindness. At least in the three cities where I have regularly driven over the last 20 years, the colours are distinctly different.
OT: When I was kid I remember that all cars in Paris had yellow front lights which gave the city a special and unfamiliar look. Is this still the case?
Edit: Just googled myself, it's called Selective Yellow[1] and the reasons are interesting and depending on the source different [1][2].
A large institution I'm aware of that installed thousands of these lights in indoor and outdoor public spaces during the recession. The hook, which was a ROI written by the lighting companies and fed to the facility people indicated that the lights would save some ridiculous amount of money, factoring in fewer bulbs, fewer service calls, etc. The reality is that total cost is only marginally better.
The problems are twofold -- the lights don't last as long as advertised, particularly in enclosed fixtures. Warranty claims are difficult, and they cost 7-12x the legacy bulb. In reality, they are spending more than they did with legacy bulbs because they need to dispatch people when they (frequently) break vs. do scheduled maintenance.
The other issue is that new bulb tech is harder to buy thanks to the carnival marketplace. Legacy bulbs involved a janitor looking up a part number written on the fixture. Exceptions were limited -- exhibit space needed a fancier bulb. The new stuff has different color temps, intensities, etc that nobody understands and many people disagree about.
I'm skeptical about cost savings in these programs. If there are cost savings, my guess is that the savings is stemming from the "managed service" model that the vendors push (i.e. Contractors making $20/hr, vs a $45/hr city worker) and less from the electric bill.
I'm curious if anyone has tied the recent talk about different hues of light and their effect on human health and citywide lighting? I'm referring to the types of stuff Dave Asprey and bulletproof people talk about. Could you influence the community as a whole through lighting choices?
The larger problem with newer headlights isn't so much the HID or LED source, but the fact that nearly all cars are coming with projectors. Even halogen looks really bright to oncoming traffic when it's focused down to come out of a small-diameter source. I would be interested to see what we could do with lower power LEDs in an array -- same or more light actually hitting the road, but potentially much less glare to oncoming drivers.
Legal limits on headlight intensity have been increased several times. In the US, before 1978, it was 37,500 candela. Now, it's 150,000. This isn't just a technology issue; it's not terribly difficult to get 150,000 candela from a halogen incandescent bulb given a decent size reflector or a focusing lens.
Seems like household bulbs are either too yellow or too blue/white. Our choices are now dim yellow or harsh unnatural white. For me, the GE Reveals and old "standard" bulbs were perfect.
It literally changes the colors we see in our environment. Always took colors/lighting for granted until the war on incandescents.
Yeah, don't want the harsh white, but once upon a time there were bulbs that created natural warm light that wasn't dim and didn't cause the environment to yellow out.
Sao Paulo's former mayor Fernando Haddad's popularity took a plunge as soon as he announced that he was replacing all conventional bulbs with LED. The population thought that was a step backwards and instead elected the host of the Brazilian version of "The Apprentice". Sound familiar?
The sodium lamps never really caught on where I live, but we had the pleasure of them along a few select stretches of motorway, though by now they are long gone.
I liked them. Pleasant for night driving, easy on the eyes, and not blending in with everything else.
I image I would like them even more today. Eyesight fine, but dammit, with age you start loosing contrast after sunset. Driving the city at night, especially in rainy weather, gets really tiring after a while. And the headlights on newer cars seem to be in fierce competition of unpleasant blue harshness.
Several years ago this was a big issue in Los Angeles for filmmakers - there was a distinct look that people expected from a night scene in Hollywood, sunset, or pretty much anything in LA. Filmmakers would hunt down the last few neighborhoods to switch and film there before the streetlights turned blue.
Now to get the same effect, you've got to provide your own lighting.
I never understood why westerners like orange light. I find it depressing. The same goes for the lights at home. I make a point of always replacing the 2700k bulbs with something whiter.
>What culture are you from that you consider "westerners" liking too much orange?
Probably Asia. I believe the aversion to warm colors stems from skin tone, as sallow predominates in that region of the world. In the "seasonal coloring" used by many women (such as my wife) such a coloring would be termed "Winter", and is best complemented by a blue-cast. In Northern Europe and its diaspora populations the warm-cast-favoring "Spring" and "Autumn" predominates.
> I never understood why westerners like orange light.
It doesn't interrupt our circadian rhythms at night the way blue light does. We westerners also have an obsession with street lights. Unless you live someplace where your nearest neighbor is 10 miles away, you have street lights shining through your windows all night long.
Are there any EEs on HN who can explain a characteristic failure mode of LED lamps---as well as LED-lit commercial signs---that very bright, metronomic 2--5 Hz flashing that they do? I've seen it happen to street lamps, desk lamps, commercial signage, traffic signals...it's not the usual 50 or 60 Hz flicker, but a distinct failure mode, regularly flashing a few times a second, like a circuit breaker resetting, but faster.
It's distinctive to LEDs, must be something in the power supply. But why do so many LED lamps do it?
For street lights, it might be interesting not to have "white" LEDs but rather a combination of single-line red, green and blue LEDs. Without the phosphor, they should be more efficient, and it would help handling the light pollution for astronomy, as one could use selective filters. It would also make it trivial, to get the desired color temperature by balancing the three colors.
They started switching over to LED lights in Brooklyn a year or two ago. At first, it was unbelievable eerie, but I've gotten used to it. There was kind of a connection to the yellow lighting and being out at night, and that's gone now. It's just shitty daytime at night now.
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Why is Chicago's lighting important? It's not exactly new - I live in a small rural town in the south west of England (Yeovil, Somerset). We sprouted new lighting spectra last year (or earlier).
Chicago - major city (you've heard of), Yeovil - small town (you haven't).
It's not important per se––it's just that the orangeness of the night light is very iconic for anyone who's lived in or spent any time in Chicago. I went to college there, and late-night walks home in a completely ORANGE world are one of my most vivid visual memories.
It gets even stronger on cloudy nights in the winter, when all that orange is just bouncing back and forth between the (reflective) snow and clouds.
Chicago is a much bigger city than Yeovil. Chicago Magazine is a publication that gets most of its readership from Yeovl. The fact that Chicago is far bigger than Yeovil means that changing its lights is a much bigger and harder to revert undertaking than it was for Yeovil. Newness is not the most important thing.
The new lamps are definitely much bluer than the current sodium lights, which gives the street a different, unfamiliar feel. The article suggests the city ultimately adopted 3000K lamps, but it definitely feels like the pilot program used 4000K ones, they looked very cool.
Another interesting development with these so-called "smart lights" [1] is that the city can potentially modulate brightness on a street-by-street basis, and asking different neighborhoods to weigh in on where they want the lamps to be brighter (or maybe, if they want them dimmer on side streets etc). This sounds like a very good change - customizing street lights based on neighborhood requirements is a very nice development!
[1] https://www.cityofchicago.org/city/en/depts/cdot/supp_info/c...