POLL: What is your favorite color for a night-vision-preserving flashlight?

Red is often recommended for preserving night vision, because the rod cells in our retinas are fairly insensitive to red light. However, I personally find that dim green light is much more pleasant, whereas red light is either harsh and mildly painful, or too dim for me to see clearly. (judging by the colors of about half the car dashboards on earth, I'm not the only one.) I'm curious to see which colors other CPFers prefer.

Please don't re-hash the old arguments about the sensitivity of rod cells, or insist that shorter wavelengths must ruin night vision regardless of what a person thinks they're seeing. Everyone's eyes are different, and there are lots of factors (such as relative concentrations of different-color cone cells, and the exact focal properties of each person's eyes) that can cause shorter wavelengths to be a better compromise for some people, while other people can see just fine with longer wavelengths. That debate is just an extension of the Cool Tint vs. Warm Tint debate, and it has been beaten to death so thoroughly that it can't even be identified by dental records.

I'm just interested in collecting people's personal preferences based on experience. Also, if anyone has a favorite single-color flashlight that they use for preserving their night vision, feel free to share suggestions in case others are having trouble finding what they need.

Red is best because it activates the cones in the eyes (which are used for daylight vision and color vision), but doesn't activate the rods. The rods are therefore preserved for night vision.

If you use a shorter wavelength (like green or blue), the rods are activated and you lose them for night vision. The only way to prevent that is to use a very dim light. So dim that you won't be able to read with it.

So red allows a much brighter light to be used without ruining night vision.

A good white (or NW or HCRI) sub-lumen level followed by a 2-4 lm low are fine for me, so I voted "other."

reppans said:

A good white (or NW or HCRI) sub-lumen level followed by a 2-4 lm low are fine for me, so I voted "other."

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Beat me to it!

markr6 said:

Beat me to it!

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Same here.

I voted deep red, by which I mean 660 nm.

A lot of "red" lights are actually in the range of 625 - 630 nm which appear brighter but are rather more orange than red. For me these are not as ideal for preserving night vision - dimmer and redder is better.

Etsu said:

Red is best because it activates the cones in the eyes (which are used for daylight vision and color vision), but doesn't activate the rods. The rods are therefore preserved for night vision.

If you use a shorter wavelength (like green or blue), the rods are activated and you lose them for night vision. The only way to prevent that is to use a very dim light. So dim that you won't be able to read with it.

So red allows a much brighter light to be used without ruining night vision.

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Couldn't resist, huh? Please read the first post; I already summarized that same info. I also asked for people to please not insist that colors other than red can't possibly be used effectively, because you're invalidating other people's firsthand experience, and that's rude.

I prefer blue, but haven't tried green much, so I may have to see about that.

This is a great idea for a poll, by the way

fyrstormer said:

Couldn't resist, huh? Please read the first post; I already summarized that same info. I also asked for people to please not insist that colors other than red can't possibly be used effectively, because you're invalidating other people's firsthand experience, and that's rude.

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LOL I wasn't going to say anything...figured you missed it

Other: White

Preferrably neutral white... As a compromise. No need for high cri in night vision situation. The colors wouldn't be recognizable anyway (or they would be very faint).

I would be interested in trying deep red (660nm-680nm) but they are very rare... Not interested in other colors, unless it is a tritium light (I have a big tritium tube as a night light in bathroom).

If you're cool with installing your own LEDs, RapidLED sells a 660nm Philips Rebel, and SuperBrightLEDs sells a 660nm 5mm LED with 15- or 30-degree beam widths.

I have considered modding one. I have (for example) a 1*AAA Balder that would be very easy to mod (not glued etc.). Someone else asked about deep red leds in Homemade and modified sub forum some time ago and was suggested Mouser and Farnell (I think). The prices for the leds you suggested are very good but unfortunately the shipping costs are pretty high to my country (+those leds/boards wouldn't fit Balder directly, neither would they fit another more powerful light that I could use). Anyway, thanks for the tip.

fyrstormer said:

Couldn't resist, huh? Please read the first post; I already summarized that same info. I also asked for people to please not insist that colors other than red can't possibly be used effectively, because you're invalidating other people's firsthand experience, and that's rude.

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I didn't realize you were in charge of the thread. My mistake.

I am pointing out that RED is the proper choice, for very valid scientific reasons. Rehashing those scientific reasons seems appropriate, considering any other color is a much poorer choice. Or maybe you're a difference species, and your eyes work differently. Again, my mistake for assuming everyone posting is human.

RED allows you to use a relatively bright light without ruining your night vision.

Other colors requires lux values so low that you can't see colors anyway, and must be so low (WAY less than moonlight) that reading is impossible. So you may as well enjoy a brighter light you can actually see with, and use RED.

You can pretend other colors are better, but you'd be wrong.

Oh, and if you really believed other colors are valid, then missing white in your poll is a pretty glaring omission.

For me it was useful as I didn't know the scientific explanation: I had just read red was better and my eyes confirmed it but didn't know why!
RED definitely for me though I do find green more pleasing to the eye.

Nichia 219, seems to make things look like they're natural color at night.

Etsu said:

I am pointing out that RED is the proper choice, for very valid scientific reasons. Rehashing those scientific reasons seems appropriate, considering any other color is a much poorer choice. Or maybe you're a difference species, and your eyes work differently. Again, my mistake for assuming everyone posting is human.

RED allows you to use a relatively bright light without ruining your night vision.

Other colors requires lux values so low that you can't see colors anyway, and must be so low (WAY less than moonlight) that reading is impossible. So you may as well enjoy a brighter light you can actually see with, and use RED.

You can pretend other colors are better, but you'd be wrong.

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Yes, that is the usual scientific explanation behind night vision but there are other factors, too.

Edit: I originally had some more thorough considerations and a specific question here, too, but decided to study the subject more by myself first.

sampson2269 said:

Nichia 219, seems to make things look like they're natural color at night.

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We are talking about night vision. The illumination levels are so low that everything is essentially black and white.

I am not going to argue with you, Etsu. I made it very clear in the original post that I wanted to find out people's personal preferences, and not turn this thread into another pointless debate. If you are comfortable dismissing the firsthand observations of other people on the basis that it doesn't agree with what you've read in a book, you are unfortunately welcome to do so, but you have no business claiming to have a scientific perspective if you're willing to throw away data because it doesn't fit your foregone conclusion.

I don't have direct control over the content in this thread, but I did start the thread with a clearly stated purpose, so I can still tell you you're being an *** if you decide to hijack it for your own satisfaction.

If you're cool with installing your own LEDs, RapidLED sells a 660nm Philips Rebel, and SuperBrightLEDs sells a 660nm 5mm LED with 15- or 30-degree beam widths.

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Thanks FS - I use Osram 660nm emitters from Mouser (the delivery charges are a pest but I usually lump them in with some other stuff I need to order). I've successfully modded an HDS and an M20 Crimson with these - not sure if I'll be able to get at the red LED in my Chameleon though.

I added to the deep red list. From deep sky telescope use, hunting distant galaxies & dim nebula using 12-16 inch telescopes, averted vision. An old mag 2aa with deep red filter worked well to see the charts. ....and then still see the target through the eyepiece.

Another trick that works well is wearing an eye patch over the eye you want to use with the telescope when you need to turn the light on, so it doesn't get affected at all, regardless of which color light you use.