Originally Posted By: Bingley
... Second, I started reading about the debate of light colors. Apparently people are preferring green over red for saving night vision these days. But then the more important thing is not to have a light source that is too bright -- no matter what color, a light that is too bright will make you lose your night vision, forcing your eyes to take time to readjust. Does color make a difference for the Micro Photon? Is it too bright?

Links in case anyone is interested, here are two links I read: Dough Kniffen,Astrolight for Visual Work, or Go for the Green, which is cited in Bryan Black, Navigating the Dark: How to Preserve Your Night Vision. ...


Where to start... First, the writer is primarily interested in night vision for Astronomy/Star Gazing, which is not a universal interest when it comes to night vision. Second, in one of the links there is a statement that reads:
Quote:
...Conventional wisdom dictates that your chosen, appropriate, source of illumination should be primarily red although spectrally pure red is even better. The conventional wisdom is wrong! Millions of observers are unnecessarily compromising their night vision each time they use a red light to read their charts. Why? Because monochromatic red light must be many times brighter than polychromatic green before we can see with it. ...
...Much of the myth has certainly been supported by the existence of numerous studies showing red light, of a given intensity, has less effect on night vision than other colors. While this is true, a light source that has the least effect on night vision is not the same thing as a light source that will allow visual perception at the lowest possible level of illumination. ...
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It’s a cones & rods thing within the human eye. The Rods and Cones of the Human Eye

Human eye color receptors are less sensitive to red and are very sensitive to blue. Green sensitivity falls between the two. He uses less green light because the human eye doesn’t need an intense green. However, it doesn’t take a lot of blue or green to desensitize the rods. When the human eye is subjected to blue & green, the rods are suppressed/turned off and it takes time to bring back that rod sensitivity once gone. Red does not have the same effect, so with a red light, your rods can continue to function receiving the all those shades of gray between light & shadow.

It takes what, 20 minutes sitting in the dark to bring your rods up to an acceptable level of night vision sensitivity and this guy then wants us to use a green light? Try it yourself. Get your eyes nicely night adjusted and then use a red light to read a book. Turn off the light and see if your eyes are still night adjusted. Then do it with a green light...

One of my favorite lights for night vision is a FourSevens 1xAAA Atom that emits two levels of red, Moonlight and Low. With night adjusted eyes, the moonlight level of red is all you need for close-in work.

FWIW