eyes at night and LED.

Interesting. However, I don't drive with my flashlight.

Seriously, from my experience, I find the warmer colors much much easier on my eyes. This is especially true once my eyes have adapted to the dark. This is one of the reasons I couldn't stand most headlamps and lanterns in the early LED days. That eye blistering blue gave me headaches. I guess this could be a story of how Nichia saved my brain?

Anecdote from a car company couldn't be any more hilarious. I personally find warmer tints 3500-4300k to be much better on my eyes. Warm tints seem to provide better depth perception and penetration of fog and dust. While cooler tints provide slight better acuity and can see traffic signs better.

Mercedes will say anything to stroke the ego of their customers.
When the sun angle is anywhere close to that of car/truck headlights, the CCT is no where near 5000K.
Closer to moonlight would be more appropriate.

I know, that in 90% of situations, indoors or outdoors, low light or pitch darkness, I prefer a warmer color temp. Higher CRI of course but no higher than 4500k. This goes for automotive lighting especially! Helps me differentiate between objects and aids in depth perception as well.
I find when driving, the cooler color lights (mine and theirs) causes severe glare and excessive eye strain, and in prolonged exposure, headaches.
About the coolest lighting I have in my house is my garage shop light (LED 5000k) and over my lab bench (100w MH 4500k). Anything higher just makes me sick to my eyes.
My wife's ex had installed 6000k HID bulbs in her car about a year before he left, we both hated them, I replaced them with stock 4000k bulbs and she and I both agree, much better.... And fewer oncoming people flashing their brights at us as well.

I really don't mean to be that guy, but I have always liked cooler lighting. I'm young enough my first flashlight was indeed LED. I'm not that young, it was very blue. Almost violet. But it developed into a love I still have today. I prefer my cheaper cool colored light as my EDC, just because it seems to strike my memory. In the sake of usefulness, technically, warmer lights will go through some transparent things better than others. Dust vs water penetration is an example where the extreme cool vs warm might penetrate differently. The warmer light is the literally warmer it is. Our eyes are most sensitive to green technically, but green/cyan isn't necessarily going to bounce of things with the best reaction. Truly white light will have a strong rainbow effect when shining through a prism. That can tell you your color usefulness when using your light to see color.

RickZ said:

Truly white light will have a strong rainbow effect when shining through a prism. That can tell you your color usefulness when using your light to see color.

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Thats a great idea! Do you have any LED comparison pictures?
Im going to have to get a prism to compare my lights, I have a few with High CRI, each has a different LED and tint..

RickZ said:

I'm not that young, it was very blue. Almost violet. But it developed into a love I still have today. I prefer my cheaper cool colored light as my EDC, just because it seems to strike my memory.

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I grew up with tungsten and have come to love neutral white or daylight. It don't matter to me.

Parrot Quack said:

I grew up with tungsten and have come to love neutral white or daylight. It don't matter to me.

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You grew up with lights rated in BTUs? ☺
Myself, I thought like others,
never grew up so it's a moving target.

Its the same in my workplace theyhave replaced all lighting with daylight systems and........... none of us like it , I suffer headaches from it too. Warmer old skool bulbs just feel nicier.

Sadly I don't have pictures ready as my cheap phone doesn't have the best camera it wouldn't help, plus my glass prism is in storage, so right now I just test using a makeshift prism from a broken piece of glass, be sure to TEST your prism by looking at it through the sunlight during daytime. Prisms will show you a general relationship, but be sure to remove the lense and reflector to prove the frequency and span of light is coming from the emitter, because the lense will alter the color. Also obviously be sure the resulting rainbow is shining on a white wall, not creme or egg or stone. Then you can of course see how the lens effects the light when you put it back on.

The frequency of emission is narrow if you see less colors, and the brightness of the colors will represent the majority of the color emitted. A true green laser, for example, will only come out green.

WarRaven said:

You grew up with lights rated in BTUs? ☺

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Kind of.....LOL!

RickZ said:

be sure to TEST your prism by looking at it through the sunlight during daytime. Prisms will show you a general relationship, but be sure to remove the lense and reflector to prove the frequency and span of light is coming from the emitter, because the lense will alter the color.

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I just got back from the store with my new prism. I looked for my good one, but it must be in storage like yours.

I can barely get any colors from the plastic prism using sunlight, and none at all from using my Maratac. I do not have the skill or inclination to test the bare LED, Im just shining the light at the prism, rotating in various positions.. so far Fail

I was so hoping to see an LED rainbow today.. I was all set to take pics of the result of testing a 4500k N219a, 3000k XP-G, 3000k XP-L, 5800k XP-G2 and 5800K XP-L

I hope somebody with a quality prism posts some photos of various of the typical LEDs in use in our lights.

Crystal ornaments?

Edge of sheet of glass?
Like a lens.

jon_slider said:

I just got back from the store with my new prism. I looked for my good one, but it must be in storage like yours.

I can barely get any colors from the plastic prism using sunlight, and none at all from using my Maratac. I do not have the skill or inclination to test the bare LED, Im just shining the light at the prism, rotating in various positions.. so far Fail

I was so hoping to see an LED rainbow today.. I was all set to take pics of the result of testing a 4500k N219a, 3000k XP-G, 3000k XP-L, 5800k XP-G2 and 5800K XP-L

I hope somebody with a quality prism posts some photos of various of the typical LEDs in use in our lights.

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Take into consideration background, distance between the prism and background, background color (white paper when outside, a white wall while indoors) you may have to use the prism reflecting sunlight in the shade of a tree, using the light that makes it between the leaves to shine through, and the shade of the tree will make the background dark.

Other prisms to test the span of frequencies would be 1) whether or not you can see a definitive rainbow when shining the light on to sprinklers or water mists in the middle of the night -������������������ most LED lights have a hard time with this because, indeed, they have a relatively narrow spectrum when compared to incandescent and florescent lightning, this us one if any, disadvantage to LED lights, so seeing a partial rainbow, like red yellow blue is a good sign.

Another prism is a crystal ball, though not the clearest and will give a vary narrow rainbow that is hard to distinguish, and finally another kind is a DVD disk, there should be a rainbow there too, or even one of those disco balls, it should reflect the different colors as well.

In anything you use, especially not a typical prism, please make sure you have a good control flashlight, the one you keep coming back to, and use it as a comparative between LED and hid or incandescent BEFORE you compare the tiny slight differences between various LED lights, since the differences between similarly priced LED will be almost impossible to tell. Reflectors and lenses on the flashlights have significant differences of light color.

The best test for spectrum will be shining the light on a colorful shirt, like a tie die shirt with all it's colors, and take a picture, then take the same picture with a different light, do all this with zero interfering light in total darkness, and you will compare the photos with a good camera, combine the opinion you have with direct observation with you and other people's opinions on the differences between the two photos you have. AMD ONLY COMPARE TWO LIGHTS AT A TIME.

I should make it clear though, the color of the light is completely different than the spectrum of the light , since the color is the resulting light when it bounces into your eyes, it will not represent the degree of spectrum, accept for violet and indigo, vs red and yellow, which are certainly inferior in spectrum to white, MOST of the time.

Maybe the added contrast at 5000k helps them better see out into the distance, who knows. We'd need to see the specifics of the study. Overly warm lights paint everything in a yellow-orange drab, so everything tends to blur together-- no matter how high the CRI. However, there's no doubt they penetrate fog and dust easier.

I personally prefer anything that looks closer to real sunlight. 5000k lights are preferred. Ideally I'd want a 5500k 100 cri light.


With the sheer disdain for anything even approaching 5000k, I'm surprised a lot of people can even stand the 6500k diffused daylight that enters their home during the day.

twistedraven said:

I personally prefer anything that looks closer to real sunlight...

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me too, at sunset.. LOL
I have some LED lights called HUE, I use them to wake up to a nice red glow which changes to more orange, then golden, as I go from bedroom thru living room, to kitchen

and fwiw, its not that I dont want FULL SPECTRUM light, even at 6500K, the issue is with our flashlights, the CRI is very low at that Cool Blue Color Temperature, and the LED output spectrum lacks reds. In order to get an LED to produce red light, a coating is added, which reduces brightness, and warms the tint..

So, to get full spectrum noon sunlight from an LED is not going to happen.. I can get you fuller spectrum sunset and candle tint though, if you can learn to enjoy the soothing warm glow of high CRI Leds .. LOL

twistedraven said:

sheer disdain for anything even approaching 5000k

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the disdain is for the lack of full spectrum, aka LOW CRI, not the Color Temperature

then again, Im very biased, I carry two 3000K LED lights that I use the majority of time, and I prefer the warmer of the two for most of my personal needs, and I only carry one 5800K LED light (that sees very little use). And my glovebox has a 4400K N219 light