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Some cities are taking another look at LED lighting after AMA warning

washingtonpost.com

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Re: Some cities are taking another look at LED lighting after AMA warning

#41

Post by TeMPOraL »

keenerd wrote: post #36
fian wrote: post #34

Earlier quoted context omitted.

> Moonlight is around 4100K. So it is even more "natural" than 3000K. Should we blot out the moon next? I was on a hike in July during a full moon and those who were sleeping in open air (no tent or bivy bag) struggled to sleep through the night due to the moonlight. This was in the North West of Australia, so daytime maximums were around 35C. It was too warm at night to zip your tent or bivy closed, so where possibl…

No one carried a bandanna that they could use as an eye mask? I've done that even when the night time low was 35C.

In situations like that I use any random piece of clothes as an eye mask, so yeah, I don't see a problem either.

Re: Some cities are taking another look at LED lighting after AMA warning

#42

Post by sokoloff »

raziel2701 wrote: post #31
phasetransition wrote: post #25

I'm head of engineering for a company that designs outdoor luminaires for industrial environments, but not street lights. We use LED and other technologies. Like so many things in life, there are aspects of the AMA directive with potential cause for concern, but also combined with a mixed bag of scientific underpinnings. If you have specific questions about LED physics or human vision, I'm happy to give them a go. I…

What temperature LED light should I have for my bedroom?

For sleeping? I recommend Zero Fahrenheit Fahrenheit.

Re: Some cities are taking another look at LED lighting after AMA warning

#43

Post by harlanlewis »

fian wrote: post #34
keenerd wrote: post #29

Let's break down their claims. > unseen blue light I have unread negative comments about this sloppy writing. They also repeatedly use the word "intense" incorrectly. Intensity refers to candela. Not lumens or temperature. > The original LED streetlights had temperatures of at least 4000K, which produces a bright white light with a high content of unseen blue light. 4000K is actually considered fairly mellow. Above 6…

> Moonlight is around 4100K. So it is even more "natural" than 3000K. Should we blot out the moon next? I was on a hike in July during a full moon and those who were sleeping in open air (no tent or bivy bag) struggled to sleep through the night due to the moonlight. This was in the North West of Australia, so daytime maximums were around 35C. It was too warm at night to zip your tent or bivy closed, so where possibl…

Even worse is the extreme latitudes in summer! I tried sleeping under just a mosquito net in Alaska when the sun stayed up until 2am and rose again by 4. I brought a sleeping mask but found it hard to keep on, as we'd encountered three separate grizzlies earlier that day…

At lower latitudes, a full moon over snow is stunning and surreal when you can get away from local light sources - no flashlight required. Light at night (of appropriate color temp) is quite natural.

Re: Some cities are taking another look at LED lighting after AMA warning

#44

Post by andrewaylett »

klipt wrote: post #24
criley2 wrote: post #21

Earlier quoted context omitted.

>They should be banned in favor of lower-color-temperature lights. As the article indicates, they are less effective at disrupting sleep than a LCD monitor or smartphone. If we're banning an outdoor light for being less disruptive than your phone, should we also mandate Flux style warm color phones at night by law?

Why not. I already use flux on my laptop and would love it if my phone supported that too.

If you've got a phone supported by CyanogenMod, it has a very nice mode called "LiveDisplay" which will adjust the phone screen's colour temperature on the fly based on time of day and both the brightness and colour of the ambient light.

Re: Some cities are taking another look at LED lighting after AMA warning

#45

Post by sandworm101 »

fian wrote: post #34
keenerd wrote: post #29

Let's break down their claims. > unseen blue light I have unread negative comments about this sloppy writing. They also repeatedly use the word "intense" incorrectly. Intensity refers to candela. Not lumens or temperature. > The original LED streetlights had temperatures of at least 4000K, which produces a bright white light with a high content of unseen blue light. 4000K is actually considered fairly mellow. Above 6…

> Moonlight is around 4100K. So it is even more "natural" than 3000K. Should we blot out the moon next? I was on a hike in July during a full moon and those who were sleeping in open air (no tent or bivy bag) struggled to sleep through the night due to the moonlight. This was in the North West of Australia, so daytime maximums were around 35C. It was too warm at night to zip your tent or bivy closed, so where possibl…

Perhaps this is our bodies telling us something, a piece of our evolution. Perhaps we aren't meant to sleep in the open. We are easy prey at night. Sleeping in moonlight, out in the open, is dangerous for prey animals. A dislike for sleeping in moonlight might therefore be a survival tool. Those uncomfortable with moonlight were more likely to be sleeping under cover and less likely to be hauled off by lions.

Re: Some cities are taking another look at LED lighting after AMA warning

#46

Post by dpark »

ianai wrote: post #15
Bud wrote: post #12

Earlier quoted context omitted.

No. The lights aren't effective at keeping sleepy people more awake in the moment. They're effective at disrupting sleep over time by disrupting the hormonal system. They should be banned in favor of lower-color-temperature lights.

The blue light also burns out retinae. It's been linked to cataracts. It seems like an industrial regulation is needed to me.

Citation? That's a bold claim.

As phrased, it also sounds really far-fetched since cataracts are not a disease of the retina. Maybe that's a problem with the phrasing and not the claim, though.

Re: Some cities are taking another look at LED lighting after AMA warning

#47

Post by thought_alarm »

keenerd wrote: post #29

Let's break down their claims. > unseen blue light I have unread negative comments about this sloppy writing. They also repeatedly use the word "intense" incorrectly. Intensity refers to candela. Not lumens or temperature. > The original LED streetlights had temperatures of at least 4000K, which produces a bright white light with a high content of unseen blue light. 4000K is actually considered fairly mellow. Above 6…

My city used old-style mercury-vapor street lights up until the early 80s. For those who have never seen these lights, they have a bluish-white appearance but emit light only at a few very specific wavelengths, and almost none in the red spectrum. The effect is that under these lights a red car would look strangely black while everything else more or less looked normal color. I loved the effect.

I have fond childhood memories of seeing my street bathed in the bluish-white light from these street lights, especially during those long winter nights when the ground is covered in white snow. I am quite certain that these street lights did not produce a generation of "physiologically unwell" people.

My city has now begun switching to LED lights and I think they look terrific.

Re: Some cities are taking another look at LED lighting after AMA warning

#48

Post by _0w8t »

honkhonkpants wrote: post #23
_0w8t wrote: post #16

While that may improve sleep, it may also made driving less safe. With blue light it is easy for eyes to focus. In fact there is a theory that significant increase in myopia during the last 100 years is caused by eye work under artificial light without blue color, like from ordinary light bulb... Edit: I should have written "without blue light in spectrum eyes work harder". Basically any deviation from the spectrum o…

First time I've heard that it is easy to focus blue light. https://www.google.com/search?q=is+it+hard+to+focus+on+blue+...

I should wrote about focusing in light without blue component, not focusing under blue light.

http://www.eyedolatryblog.com/2014/02/myopia-may-be-reversib...

Re: Some cities are taking another look at LED lighting after AMA warning

#50

Post by keenerd »

sandworm101 wrote: post #39
keenerd wrote: post #29

Let's break down their claims. > unseen blue light I have unread negative comments about this sloppy writing. They also repeatedly use the word "intense" incorrectly. Intensity refers to candela. Not lumens or temperature. > The original LED streetlights had temperatures of at least 4000K, which produces a bright white light with a high content of unseen blue light. 4000K is actually considered fairly mellow. Above 6…

I would also submit that Kelvin is not an appropriate reference for the colour of LED lights. Kelvin only makes sense when discussing blackbody emissions, it is essentially a description of temperature. LEDs do not create light via simple heating. Their spectrum is not the smooth blackbody curve that the kelvin scale suggests. It is in fact a combination of several strong emissions at narrow wavelengths that combine…

While I agree with you from a standpoint of accuracy, Kelvin is still really useful. It also happens to map pretty nicely to how we perceive color.

The N-step MacAdam ellipse on a 2D CCx/CCy plane is what gets used when you dig into tint, but people love to reduce complex systems to a single number. And if you want a single number, temperature is the best we have.

I'm curious what your suggestion might look like in practice because it would be even more complex than the MacAdam ellipse.

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