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Why so many control rooms were seafoam green (2025)

bethmathews.substack.com

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Re: Why so many control rooms were seafoam green (2025)

#181

Post by drzaiusx11 »

roughly wrote: post #29
jscheel wrote: post #14

I got through this entire article before I realized it was written by someone I worked with back in my agency days. Beth is an awesome designer with a great eye. Nice to see her on the front page here. Now, to the content: I often wonder how much we have lost with our endless quest for minimalism. We can't even make buttons look like buttons anymore. Affordances have become anemic at times. Designers who think and ca…

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…

Another effect observed with LED street lights, especially in my area, is that many have shifted from white light to purple as a widespread manufacturing flaw causes their phosphor coating to fail.

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.

Re: Why so many control rooms were seafoam green (2025)

#182

Post by adrian_b »

SyzygyRhythm wrote: post #47
roughly wrote: post #29

Earlier 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…

The lamps that use alkaline metal vapor instead of a noble gas have better energy efficiency, because of a lower ionization potential, which leads to a lower voltage drop on the lamp. Therefore they have been preferred for lighting instead of neon lamps and the like.

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.

Re: Why so many control rooms were seafoam green (2025)

#183

Post by adrian_b »

numpad0 wrote: post #136
SyzygyRhythm wrote: post #47

Earlier 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…

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.

There are 4 important properties for the substance used in a gas-discharge lamp.

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.

Re: Why so many control rooms were seafoam green (2025)

#184

Post by rapnie »

adrian_b wrote: post #176
mcfly_c-137 wrote: post #93

Earlier 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.

There are 2 kinds of sodium lamps, low-pressure and high-pressure. 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 justifi…

In my area and esp. in the countryside they have green led lighting on various roads as an innovation, with the reasoning that is both least disturbing to wildlife, and best for human vision to see sharply. The light color takes some getting used to, but I am quite a fan of it. Esp. when cycling at home at night through the fields it makes things seem extra serene and peaceful.

Re: Why so many control rooms were seafoam green (2025)

#186

Post by adrian_b »

josephg wrote: post #173
nine_k wrote: post #75

Earlier quoted context omitted.

We of course can make LEDs of more or less any color. The current white LEDs are high-power blue LEDs that are covered by various phosphors to give a mix of colors for "full spectrum" illumination. Different color temperatures are produced by different mixes of phosphors. This is pretty similar to how the traditional luminescent (mercury vapor-based) lamps worked. But different phosphors have different efficiency and…

> Different color temperatures are produced by different mixes of phosphors. 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.…

For light with a narrow spectrum, it is possible to make LEDs that emit that light with high-efficiency, for any color inside 2 ranges, one from near infrared to yellow (corresponding to semiconductor phosphides and arsenides) and one from blue to near ultraviolet (corresponding to semiconductor nitrides).

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.

Re: Why so many control rooms were seafoam green (2025)

#187

Post by adrian_b »

mikestorrent wrote: post #65
cucumber3732842 wrote: post #44

Earlier quoted context omitted.

I'm sure tons of people along the way "noticed" but if you're selling LEDs or you're paid by the LED people to create marketing to convince people that LEDs are gonna save the planet, you're not gonna bring that up.

IDK if you've noticed but we are all lighting our house with bulbs that use 1/10th the amount of electricity as incandescents did. I like the color spectrum of a real lightbulb better, too, but not enough to pay 10x in power. I make up for it by using all kinds of random bulbs all over the place so that the aggregate light in the room fills more of the spectrum than if I coordinated them all to be the same.

For indoor lighting, LED lamps are indeed the right solution.

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.

Re: Why so many control rooms were seafoam green (2025)

#188

Post by adrian_b »

aliher1911 wrote: post #77
mikestorrent wrote: post #65

Earlier quoted context omitted.

IDK if you've noticed but we are all lighting our house with bulbs that use 1/10th the amount of electricity as incandescents did. I like the color spectrum of a real lightbulb better, too, but not enough to pay 10x in power. I make up for it by using all kinds of random bulbs all over the place so that the aggregate light in the room fills more of the spectrum than if I coordinated them all to be the same.

Did you try using high CRI LEDs with color remperature of 2700K–3000K? When I switched from halogen to LED I did just that and the difference is not noticeable, you'll have the same yellowish tint and very natural looking colours. Even with expensive bulbs, extra longevity covers for higher cost.

I do not like 2700 K to 3000 K lamps, which are obviously yellowish and regardless how high their CRI may be they distort the colors of clothes or any other objects.

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).

Re: Why so many control rooms were seafoam green (2025)

#189

Post by adrian_b »

anymouse123456 wrote: post #175
aliher1911 wrote: post #77

Earlier quoted context omitted.

Did you try using high CRI LEDs with color remperature of 2700K–3000K? When I switched from halogen to LED I did just that and the difference is not noticeable, you'll have the same yellowish tint and very natural looking colours. Even with expensive bulbs, extra longevity covers for higher cost.

Not sure if I'm doing something wrong, or just living in a place where the power is so bad, it causes premature failures. 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.

Many complain about this, because they have been fooled into buying low-quality lamps, with bad cooling or bad electronic components.

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.

Re: Why so many control rooms were seafoam green (2025)

#190

Post by adrian_b »

dotancohen wrote: post #128
aliher1911 wrote: post #77

Earlier quoted context omitted.

Did you try using high CRI LEDs with color remperature of 2700K–3000K? When I switched from halogen to LED I did just that and the difference is not noticeable, you'll have the same yellowish tint and very natural looking colours. Even with expensive bulbs, extra longevity covers for higher cost.

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!

The color of the solar light depends on the proportion of yellowish direct solar light and bluish sky light that fall on an object.

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.

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