Night vision: Which color

J

Josh Wilson

Joined
Aug 3, 2000
Messages
232
Which color of light (red, yellow, orange or green) is best for preserving night vision and/or seeing at night. This has come up on the forums a few times and I've read several other web pages and no one seems to agree.

The only thing everyone agrees on is that red is bad for color differentiation which makes it hard to read maps and such.

Maybe we can clear the up some of the confusion on the subject.

Or I'll have to go out tonight and shine different colored lights in my eyes like an idiot and figure it out for myself :). (I think there was a thread on eye blinding idiots a few days ago, I might as well join the crowd)
 
I don't know if any of them really preserve night vision. I think they are simply dimmer than a bright white, blue-white, sapphire, or blue light, and the dimness preserves night vision.

Of course, you don't need to actually shine the light in your eyes, just use the different color beams to try to see or read by. Yellow seems too bright to me, and red and green not only distort colors badly, but have "stop" and "go" connotations you might not want someone else to mistake.

I prefer amber (orange). I sometimes take an old crookneck flashlight out at night. With the amber filter, I find I can see the ground ahead of me almost as well as with the plain white light, and it doesn't glare in drivers' eyes when I flick it up to warn them off.
 
Supposedley, certain shaeds of green are best, and you can usually find some info on this through astrological/telescop web sites...

--dan
 
RED!
Look in any astronomy/telescope catalog.
All they sell are red lights with which to read star charts.
Know why?
Red has the shortest(or is it longest) wavelength in the visible spectrum, and thus, dilates the pupils the least, keeping your eyes adjusted for the dark.
Lenny
 
That is a term US submariners use. I believe surface ships do also, but I only have personal experience on subs (10 years). When the sun sets, red lights are turned on in the subs control room and all white lights are turned out in the control room.

The reason is that if you have to come to periscope depth or surface at night you can't afford to wait 20 minutes for your night vision to develop. A collision at sea can ruin your whole day.

The Navy uses customs that have been developed over hundreds of years of life and death daily living.

RED

Take care,
bug
 
I think that you're confusing "night vision" with the "ability of the naked eye to adjust to darkness."

For "night vision goggles (NVG's)" the industry stardard is "green." Aviators (at least only ones that I've flown with) "fly" aircraft under NVG's that produce or omit a "green" light tint.

For numerous years. . .the military standard for having the troops adjust their vision (unassisted) to the darkness has been "red."

Simply, green light is cleaner and easier to filter out "white" light.

Companies are experimenting with different lens colors to try drive the cost of lens' and filters down. "Green" configurations are expensive !
 
Sorry for any confusion. I was not referring to Night Vision Goggles. I was referring to the color of our dash lights and our flashlight beams that we use to see our instruments and maps without blowing our night vision. We use red. The light seen in night vision goggles is green but that is a different question. For all I know, green may work as a flashlight or dashlight color too but I have only used red and it works.
 
Check out this link:
http://www.corvus.com/kniffen.htm



As well as this from Walt Welch, long time poster and very knowledgeable light guy:

"You guys who have been 'preserving your night vision' by using a red Photon have been deluding yourself. It turns out that the retina is most sensitive to light at about 510 nm. under scotopic (very low light) conditions. This wavelength is almost exactly that of the Photon Turquoise (500 nm.).

This is why the turquoise Photon appears so bright. This color would work best to preserve night vision, but would have to be so dim that no color is visible, only shades of gray. This is the condition when only your rods are working in your retina."

--dan
P.S. the above quote was taken from a past post from BF.com/Gadgets and gear forum, and was pasted w/out Walt's permission....
 
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