That doesn't seem right to me. Sodium (and mercury) vapor lamps are the color they are due to physics, and were chosen because they're very efficient (and long lasting). Low-pressure sodium is the best and worst of these; essentially monochromatic but fantastic efficiency. Their only advantage, color-wise, is that the light can be filtered out easily (they used to be widely used in San Jose because Lick Observatory could filter out the 589 nm light).
*edit: but it’s the overwhelmingly larger lifespan (20-30k hrs) that led to the wide adoption as streetlights. And I guess, the same is true for the change to led today, because of less power consumption.
The low-pressure lamps emit monochromatic light and they have not only the advantage of long life but they are also the only other source of light that matches the energy efficiency of converting electrical energy to light of the LED lamps.
So replacing low-pressure lamps with LED lamps does not produce any significant economic effects, it was justified only by the supposed advantage of enabling color vision.
However in many places high-pressure sodium lamps have been preferred, which have a wider spectrum, so they allow some very poor color discrimination. The high-pressure lamps have a lower efficiency than LED lamps, so replacing them was justified by energy savings.
Outdoors at night, I prefer the monochromatic low-pressure sodium lamps, but sadly LED lamps have replaced them in most places.
If you use shorter ("bluer") wavelengths, as happens with white LEDs which consist of a blue LED + phosphor, it causes people's eyes to become bright adapted and effective night vision is ruined, causing people to have much worse vision in the shadows.
Also, if you use bluer light, the lights themselves cause dramatically more glare in peripheral vision, because the shorter-wavelength-sensitive "S" cone cells and rod cells are mostly absent from the fovea (center of the retina), and prevalent in the outer areas of the retina. This is why LED headlamps on cars are so obnoxious for drivers going the opposite direction.
Also, the LEDs clobber people's circadian rhythms and are extremely disruptive to wildlife.
Finally, the light pollution caused by the LEDs is much worse for seeing the stars, which is maybe not as important as the other harms, but still kind of sad.
The sensitivity at sodium light is above 75% of the peak human vision (photopic) sensitivity.
This is a very small difference in light sensitivity. For example in the case of many sources of red light or blue light the sensitivity can be 5 to 10 times lower than the peak sensitivity.
Moreover, a perfect source of white light cannot achieve a better sensitivity than around 37%, i.e. less than half of the efficiency of an ideal source of monochromatic light at the sodium emission line.
Therefore the fact that currently LED lamps and low-pressure sodium lamps have about the same energy efficiency is caused by the LED lamps having a higher photonic efficiency and a lower threshold voltage (caused by a P-N junction voltage instead of the ionization potential of sodium), which compensate the disadvantage of using white light. A monochromatic LED lamp with the same color as the sodium lamps could have an energy efficiency at least double over the white LED lamps.
Wouldn't that be red light? But night scenes illuminated in red light have the side effect of looking nightmarish..
Yellow light a.k.a. amber light around the sodium emission line is a good compromise between energy efficiency, visual resolution and dark adaptation.
LED was presented as a sharp improvement because of the large spectrum of white light.
What they aren't good for is LED manufacturers' bottom line, and the lighting industry spent a lot of lobbying money to entice friendly politicians to heavily subsidize them with public infrastructure budgets, with those subsidies then misleadingly sold to the public as "efficient" and "environmentally friendly".
They're also not very good for reading the newspaper or doing critical color analysis. Thankfully such tasks do not need to be done at night in the middle of the street.
> Their only advantage...
How are you coming to this conclusion?! Their warmer has very meaningful effects on processing, attention and other visual effects as is the point of the discussion in the first place. It's not clear what makes you so sure that color differentiation is essential and the other effects are irrelevant.
No I absolutely don't know what matters. But it seems neither do you.
Among alkaline metals, sodium is the cheapest, so it was a logical choice.
However, the fact that it produces light of a suitable color was a happy coincidence. If sodium had produced violet light, like potassium, and potassium had produced yellow light, potassium would have been chosen for lamps.
So among the criteria for choosing sodium for lamps, the color of the light was as important as cost, ionization potential and vapor pressure.
1. For a sufficient gas pressure in the lamp, the substance must be either a gas or a metal with low boiling temperature, so that it will be vaporized by an electrical discharge.
2. The gas must not react chemically with the enclosure and with the electrodes, which prevents the use of most gases except noble gases and metallic vapors. Except for noble gases and metallic vapors, the lamps using other substances must not have electrodes, so they need a more complex and less efficient electronic system for producing a high-frequency AC discharge, e.g. using a magnetron from microwave ovens.
3. The ionization potential must be low for a good energy efficiency. Alkaline metals have low ionization potentials and low boiling temperatures, so they are better than noble gases and other metals.
4. The color of the light must be one where the sensitivity and the visual acuity are high. This narrows the choice to yellow light, i.e. to sodium, between the alkaline metals.
Way better work than whoever it is handling this LED nonsense. Why we can't find a diode that we can use to simulate the old spectra would be a fun research project.
But different phosphors have different efficiency and price. LED lamps were first introduced for interior lighting, where sun-like spectrum is welcome. Such LEDs were produced en masse and relatively cheaply. So street lighting naturally used them, because municipalities usually look for the cheapest viable option.
We likely could produce high-power narrow-spectrum orange LEDs if there was a large market for the economies of scale to kick in. You can buy deep orange LED lamps today (look for color temperature 1800K or 1600K, "amber"), but they are more expensive, because they are niche.
We can make LED light appear to be any given colour by mixing multiple LEDs. But mixed colour isn't the same as pure colour, made from a single spectra of light. Nor is it the same as true broad spectrum light - like we get from black-body radiation like the sun, or a tungsten bulb.
Its hard to tell the difference just by looking at a light. But different kinds of lights - even lights which look the same colour - will change what objects actually look like. And they probably have different effects on our sleep cycle and our low light vision. I was in a room once lit only by sodium vapour lights. The lights were yellow, but everything in the room (including me) appeared to be in greyscale. It was uncanny.
This is part of the reason why LED lights are still looked down on by a lot of old school photographers and film makers. Skin doesn't look as good under cheap LED lights.
Only green LEDs have worse efficiency, because they must be made with semiconductors for which optimum efficiency is attained at either lower or higher light frequencies.
Lamps using high-efficiency amber LEDs with about the same color with sodium lamps could be made at an energetic efficiency at least double to that of white LED lamps.
The double factor comes from the visual sensitivity being double for the light at sodium color than for ideal white light.
In reality the energetic efficiency of such LED lamps should be more than double, because they do not have losses caused by conversion through fluorescence.
[0] https://en.wikipedia.org/wiki/Moonlight_tower
[1] https://sigostreetlight.com/blogs/common-quality-problems-in...
The purple lights evoke a vaporwave/synthwave aesthetic like I'm in a bad 80s scifi movie. Unintentionally appropriate given the general state of things.
This is especially important at high latitudes where for months of the year the street lights provide more illumination than the sun for most working people.
These could just reuse the current LED lamps by just redesigning the socket. Altough the materials should be changed as the old ones (I think they were ceramic and/or concrete?) could cause serious harms if they felt over random people walking around. And, yes, they can even break concrete pavement like nothing.
I remember hearing a falling lamp+case near my home and upon falling to the sidewalk it sounded like a bomb, I am no kidding, even the floor vibrated and the windows nearly crashed. These things were really sturdy, either concrete or cement. I would love the same design but in magnesium, which can be lighter and maybe as durable, altough I know ceramic/concrete can withstand anything.
The claimed extra longevity of LED bulbs has not materialized for me.
They seem to fail at roughly the same frequency that incandescent bulbs did in my home, which makes them about 10x to 15x more expensive.
I have many Philips LED lamps bought some 10 to 15 years ago, which were put in Edison sockets for incandescent lamps, and none of them has become defective during all these years.
However, even at that time, it was not their cheapest model, but one that was claimed to be long-life and I believe that later they have discontinued that model in favor of cheaper lamps.
I have no idea which vendor of LED lamps might sell good LED lamps today, because I never had to search for replacements. I assume that good LED lamps must still be available, but one must not impulse buy them, but one must check carefully the specifications of the lamps and the credibility of the vendor, before making a purchase decision.
I also do not like the bluish cheap 6500 K lamps.
I consider optimum the 4000 K lamps. This appear white with only a very-slightly yellowish hue, which allows the perception of the natural colors of most objects, but it still provides a warmer sensation than a strictly neutral white color (i.e. one around 5500 K).
The actual temperature of the sun is over 5000k (yes, the k in lightbulb temperature corresponds to the Kelvin scale of temperature) but after being scattered by our atmosphere it appears cooler. And where did all that extra light go? It was scattered around, making the sky blue!
When the sky is covered by clouds, which mix the direct Sun light and the sky light, you get a color much closer to the true color of the Sun.
As it is, I compromise.
I live in a 240-volt country, though, and I've never seen a dimmer switch here.
I have also been using for more than a decade 13 W LED lamps that produce the same luminous flux as the 100-W incandescent lamps or the 23-W compact fluorescent lamps used in the past.
However, the requirements for an outdoor night lamp are very different. Low-pressure sodium lamps have about the same energy efficiency and lifetime as LED lamps, so those are not arguments for replacing them. The only thing that matters is whether you prefer yellow light or white light in a night environment. I definitely prefer yellow light, for reasons already mentioned by others, i.e. much less interference with night vision, sky light, nocturnal animals, or with my street-directed windows at home.
If energy efficiency would really matter, one could produce monochromatic amber LED lamps with efficiencies at least double over the current white LED lamps.
There’s no standards and people are clueless and confused. There are awesome LEDs, but more often you see have harsh, terrible light.
Besides, we can have LEDs in better spectrums for under 1/5th the costs of incandescents. We just hired stingy motherfuckers and don't care about the repercussions of our decisions.
Yeah I know. I love it in my house.
On the industrial side, sodium vs LED is a much closer comparison generally than LED vs incandescent. LEDs kinda suck for high bay applications.
In the US people use roughly 10 000 kwh per year.
Say we have a 40 watt bulb, say it burns on average 5 hours per day or 200 wh. In 365 days that would be 72 kwh which at 16 cents per kwh is $11.52 or 0.73% of the annual power consumption.
Say one uses 5 light bulbs. Something around $57.60. Say leds use only 25% of the power = $14.40 for $43.2 saved.
Well over 10 cents per day.
What are you going to spend your 10 cents on? lol
My whole house is neutral white LEDs except the bathrooms where we go to cool white to make it easier to clean and be sure it's clean (even if it's not spotless, there's a huge psychological benefit to not feeling like dim light is masking even more grime).
Oddly enough I'm otherwise pretty light sensitive - my current office at work has been a nightmare of trying to manage glare from badly places overheads and windows.
Going from 500w for my living room to 80w also helps a lot (and way more light and a lot less heat).
That does not make them the best choice for outdoor night lighting.
The replacement of the outdoor lighting appears to have been motivated in most cases by the desire to divert taxpayer funds towards the private companies selling such lamps, instead of by any technical reasons.
Two of my favorite classes in college were Color Studies and Typography. As a long time back end engineer, I would encourage anyone unfamiliar to spend at least a little bit of time looking into both. If you're at all intrigued, treat yourself to: https://en.wikipedia.org/wiki/The_Elements_of_Typographic_St.... It will forever change how you look at text (hopefully for the better!).
https://gjcp.net/plugins/peacock/
Yeah. Skeuomorphism isn't dead. Buttons need to look like buttons. Sliders need to look like sliders.
You just know looking at it that when you click on the little buttons, they pop in slightly as the LEDs go on and off, right? Does it look cheesy and 80s and dated? Yeah it sounds cheesy and 80s and dated too.
These are still available today, although the chromate version seems less popular for general use due to toxicity, especially (I assume) in the case of a fire.
I have painted quite a few bits of sheet metal with a sea-foam-ish blue-green/gray paint back in the day (30 years or so ago). I don't recall the manufacturer, but it was a zinc conversion coating in nearly exactly that seafoam color, which has probably stolen at least a few years of my life expectancy. The same company sold other paints in a sickly mustard yellow, and close to fire-engine red, all with slightly different chemistries, I assume for different base metals.
He used to work on yachts a fair bit and over the years he noticed the fading patterns for different colour paints.
Yellow paint would fade, red paint would fade. But if you mixed them 50/50 into orange, it wouldn't fade. That's why they had so many orange boats in the bay. Figure that one out.
Yellow pigment absorbs blue and violet light. That's what makes it look yellow, it reflects the longer wavelengths and soaks up the shorter ones. But the UV and violet radiation it's absorbing is also what gradually destroys it.
Red pigment does something similar but across a different band, it absorbs greens and shorter wavelengths, and that absorption is what degrades it over time.
When you mix them 50/50 into orange, each pigment is absorbing the wavelengths that would have destroyed the other one.
Iron oxide is anti-microbial. So a barn painted with it as a pigment will last longer vs mold and such.
It's also why large ships all have that red paint color below the waterline. In that case it's copper oxide, which helps slow barnacle growth and similar.
Back in the age of sail they even went as far as copper sheet cladding to make the wooden hulls last longer. Copper oxide pigment emerged toward the end of the age of sail / beginning of the steamship era as a more practical alternative.
It's saying "DON'T NOTICE THIS! (also, please notice this!)"
After she moved out, I put up greens, yellows, brown, and blue all over the house. It's not quite as "public pool" feeling as that original aquamarine, but it's certainly more lively than grey/white. Funny enough though, when I had a designer come in to take measurements and do a mockup for a kitchen reno... everything was back to white because that's step one in making it look "modern" even though part of the pitch is custom cabinetry that won't just look like that same white IKEA stuff that everyone installs now.
Most of the rooms in my house are painted in colors and I mostly like it but it can sometimeds feel fatiguing. I've thought about repainting in a neutral gray or green.
Anyways, the new owners tracked down my wife over some old mail, and during the conversation they thanked us for having painted it so vividly and said it was part of why they were drawn to it. They shared pics and they've done a -ton- of work, but the paint colors remain :)
We went from overwhelming color chaos of pink and green toilets, carpeted bathroom floors, and kaleidoscope wallpapers to calm, clean, and inoffensive shades of whites and "agreeable gray"s.
Soon enough people will stop thinking of those whites/grays as a fresh, low-chaos decoration decision and switch to thinking of it as oppressively boring and break out with fantastic ideas like ... green toilets and kaleidoscope wallpaper.
Sad to see how many houses are painted gray or beige in SF now. We are going to paint ours purple in protest.
[0] https://aviation.stackexchange.com/questions/16434/why-are-r...
He talked about how the wiring schematics were a maze, made worse by using only non-labeled gray and black wires with connections and mounts that were the same color made of the same material.
The exterior being gray makes sense - harder to see with human eyes. But internals? They should be massively contrasting colors for every single series of pieces to be removed so you can just follow along by color.
Sometime before that, he got a lot of flak for having neglected one of the standing rules, to label everything as you take it apart and put it back "the way you found it". He decided to break it down and put it back the way the technical documentation said it should actually go. This seems to be part of the reason his radar performed better than the others after teardown maintenance.
1. Cost savings when buying.
2. There are hundreds to thousands of wires in an aircraft, but there are NOT hundreds to thousands of different colors of wires (even if we allow for stripes, etc) that are readily distinguishable to an overworked airman hunched over in a dim, cramped avionics bay trying to fix a plane that needs to take off for a mission in an hour.
If you are lucky, the wires are numbered. But even if they are, you typically identify a wire by its connector pin and PRAY that the fault isn't a break somewhere back in the wiring harness.
Yellow would be manageable, but the wrong shade of red, purple, green, or blue (wihch, when seperating systems by colour, would inevitably get used) would be shitty to work on
[1] https://www.google.com/search?q="биррен"+зеленый&udm=36&tbs=... (search for Russian for "Birren"+green in 20th century books)
My two guesses are that it was colored like that get the pilots feel like they were in a particular environment - a familar but not exactly private or comfortable one. It's a cultural thing like if you paint a bus yellow, Americans will think of a school bus, but most other people won't.
My other guess is that they only made certain kinds of dye, and its very well possible the same factory made it that made it for bathroom tiles. In capitalism, if you don't have orange paint, for example, some company will just start making it if there's a demand.
In communism, if nobody makes it, then it's not available, until and if some comittee decides that it should be made.
Also by 1944 there would have been a ready made supply chain due to demand from the navy, which would have picked it for similar reasons and consumed it in enormous volume.
I think, practically, control rooms are chrome oxide green (you get to add as much titanium as you like - thats cheap as dirt too EDIT: it would have been lead actually in the 40s) for much the same reason that barns are red.
Also worth noting that Birren was a paid consultant for DuPont - the company that made the paint. From that perspective alone you would kinda expect he is gonna pick colours they already produce reliably at scale.
He also consulted for army, coast guard and navy so whatever colours you pick for hazard marking in an industrial setting have to be _vaguely_ congruent or you're going to cause accidents.
[1]https://www.google.com/images?q=soviet%20aircraft%20cockpits
https://images.squarespace-cdn.com/content/v1/54f84e69e4b021...
As a semi professional eagle enjoyer, if the day before was trash day, then she might have been telling the truth. I’m not joking, they have bald eagle proofed dumpsters in Alaska.
They’re basically smart seagulls with talons.
It was eagles fighting over a salmon. They genuinely do sound and act exactly like seagulls.
The German word for color is "Farbe," which is an anagram of this guy's name. So I'm chalking one more point up to the universe being a simulation written by a cheeky developer.
Either because of unconscious choice, or because some designer theorized that people would be biologically primed to prefer it.
https://faculty.washington.edu/ajko/books/user-interface-sof...
Most of our green cabinets were spotlite green. Seafoam green was rare. Both paint colors were prepared by our local sherwin Williams. The colors looked pretty much the same to me.
[0] https://www.npr.org/2024/07/19/1197961103/pantone-colors-law...
Meanwhile the Yanks stayed with mil-spec gray on a similar ship, the F-15: https://en.wikipedia.org/wiki/File:F-15_Eagle_Cockpit.jpg
#81D8D0 club, represent!
<https://news.ycombinator.com/topcolors>
Apparently tiffany green is only a Top50 contender, these days... a few years ago it had been Top10 (I hadn't checked again until this comment).
I'm not sure if it started with the teal from Windows 95's default color (hex codes vary based on Google searches), or if it was a purple-ish color from a classic Mac from school.
To this day, my work Mac is teal and my personal is purple.
After a little over a decade of service, no other color infuriates me more
Truly beautiful.
PS: I have an old friend whose dad still works at the Uranium plant in Oak Ridge. I told him that I was surprised that almost all of the facilities had been torn down, and he just looked at me straight in the face and said, “Who said it’s actually gone?” Noted.
I’d never even heard of this guy.
Heh. That explains it. I was wondering what problem people had with the comment.
I was talking about Faber Birren. The article is basically about him. Definitely a guy.
It’s always a pleasure to be “corrected,” hereabouts…
I think hospitals have moved entirely away from green, probably because of its association with industry and asylum use.
Sure. But this is not one those things.
That's one hell of a non-sequitur. In the immortal words of Inigo Montoya, I do not think that word means what she thinks it means. "The US ended the worst war in human history. Indefensible!"
The implication of the quoted sentence is that the U.S. dropping atomic bombs on Japan was awful and indefensible. The author then transitions to “but I want to talk about part of the Manhattan project that isn’t really related to the bombings.” What other explanation would there be for inserting this comment about U.S. history?
My comment was addressing the defensibility of the bombings. They may have been awful, but they were fully defensible. Japan was the aggressor, and all indications were that both the U.S. and Japan were going to see millions of casualties as part of an invasion of the home islands.
It's perfectly reasonable to make an argument that they were "not needed" in terms of ending ww2, it's much, much more difficult to argue that fewer people would have died if they weren't used.
And? Did it?
I asked about the horizontal colored bars painted on the wall in the lunch room. It was the strangest selection of colors. Each bar about a fist width. It seemed someone went out of their way to invent the most boring bland colors possible.
They told me the factory had spend over 100 k on a color expert to increase productivity. Everyone who worked there for some time knew this.
I thought I'd observe the effect. Someone was released from the factory floor for 10 minutes because they by accident worked enough hours in a row to be entitled to a lunch break, in their own time of course.
They sat down at a table carefully positioned to look straight at the color bars. And then it started! I could see on their face their internal dialog as if talking with the hundred thousand euro color consultant. The sandwich went only half way up to their mouth and they slipped into a catatonic state looking at the colors.
It was facinating, I just had to see more. Turned out half the factory had this moment with this colored wall!
I didn't have to ask them what that expression was. I could look at the wall myself and the internal dialog stated immediately: How the fuck do they expect me to pay my bills if I have to wait by the phone all week but only get two 3 hour shifts? Why did they have to spend a hundred thousand on colors to make me more productive?
It was impossible to think anything else. It was almost a blessing to go back to the high speed conveyor belt. If I didn't see it myself I wouldn't believe color theory works in magical ways.
... that just screams "green plastic stencil ruler"
Basically the same nonsensical belief as in regard the dark mode nowadays.
I don't even believe it's true. Green is just an army colour, that's pretty much it. Army uses army colours. Mystery solved.
Or maybe it's just because that's how IBM PC DOS, BASICA, etc., as well as the VT100, VT220, VT300s that I used did it.
(Also, I think displays should paint with light, and having a white background is painting darkness on a computer screen. It's particularly bad for presentation slides. A light background just screams "PowerPoint presentation".)
Maybe it even works better with the color of a clear blue sky above it.
Anyway, it's intuitive and not rocket science.
With anything, an academic can thread together a theory that neatly joins the dots to sound feasible, but my bet is that 99% of all engineers are stronger at physics than color theory.