To me, it's very evocative of mid-century industrial design. Detroit Diesel painted their engines a similar color too, although theirs is called "Alpine Green". ("Seafoam" brings to mind the engine additive too.)
Why so many control rooms were seafoam green (2025)
131–140 of 218 posts
Re: Why so many control rooms were seafoam green (2025)
#132Earlier quoted context omitted.
> that's why they were the color they were 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…
The monochromatic light emitted from sodium lamps is also close to the peak sensitivity of the human eye. Colours are not distinguishable, but contrast is much enhanced compared to “cooler” light sources. *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.
It's not especially close to the peak sensitivity of the human eye (in either bright or dim conditions), but that's entirely okay. The goal should be to not affect people's level of dark adaptation.
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.
Re: Why so many control rooms were seafoam green (2025)
#133Earlier quoted context omitted.
2700 is really cool. To the GP, if you're looking for something more like daylight but not noticeably yellow, try 3600k or thereabouts. 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!
3700-4500 is my range I like these days
If I could run different lighting after sunset, I'd run something high-CRI in your range during the day and a low-CRI 3000 after sunset.
As it is, I compromise.
Re: Why so many control rooms were seafoam green (2025)
#134Earlier quoted context omitted.
The monochromatic light emitted from sodium lamps is also close to the peak sensitivity of the human eye. Colours are not distinguishable, but contrast is much enhanced compared to “cooler” light sources. *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.
Sodium lamps were deemed dangerous for driving” because they made it difficult for drivers to distinguish shapes, since they were different from day shapes. A kid in bright 1980ies colors (Little Red Hood) would look black under those lights. LED was presented as a sharp improvement because of the large spectrum of white light.
The sodium lamps are in fact safer for driving, because they preserve drivers' night vision, which improves visibility into the shadows, and because they cause less glare.
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.
Re: Why so many control rooms were seafoam green (2025)
#135the Burt Reynolds poster
Definitely Tom Selleck, aka Magnum PI.
Re: Why so many control rooms were seafoam green (2025)
#136Earlier quoted context omitted.
I'm reminded of an article a while back talking about how the change from sodium streetlights to LED streetlights had a whole lot of unforeseen effects on animals, people's sleep patterns, driver awareness and visibility, etc. due to color changes. There was a comment on the article from an old civil engineer saying "no, these were not unforeseen, we actually did the research back in the day to figure out what color…
> that's why they were the color they were 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…
Sodium (and mercury) vapor lamps may be the color they are due to physics, but you don't have to put Na or Hg in those tubes. I don't know but Li, K, Rb, Cs should, Mg, Ca, Sr, Ba probably also work, but nobody make lamps with those elements.
Re: Why so many control rooms were seafoam green (2025)
#137Earlier quoted context omitted.
...And the old Engineer was just saying that that was the area on the spectrum they aimed for, so they found a light that emitted in that wavelength that could be technically implemented and scaled. 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.
Modern street lighting provides a way clearer view of the scene imo than the old sodium lighting. Maybe it's just brighter now.
Providing a day-like view of the scene should not be the primary goal of nighttime lighting.
Re: Why so many control rooms were seafoam green (2025)
#138Earlier quoted context omitted.
3700-4500 is my range I like these days
If I could run different lighting after sunset, I'd run something high-CRI in your range during the day and a low-CRI 3000 after sunset. As it is, I compromise.
There are LED lamps which have a "warm dim" feature so that the appear oranger as you reduce the brightness.
Re: Why so many control rooms were seafoam green (2025)
#139Re: Why so many control rooms were seafoam green (2025)
#140>In the fall of 1919, Faber Birren entered the Art Institute at the University of Chicago, only to drop out in the spring of 1921 to commit himself to self-education in color, as such a program didn’t exist.
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.