[ QUOTE ]
I can hear the clicks of Quickbeam typing his post about night vision colors.
[/ QUOTE ]
Oh boy, here we go again....... /ubbthreads/images/graemlins/rolleyes.gif
Guys, guys, guys. Green is just about the absolute worst color to preserve night vision. It's used in conjunction with electronic night vision equipment because the equipment doesn't overload when viewing green light like it does with other colors.
Exceptionally dim turquoise light is very good at preserving night vision, but if you can ID the color of the light, it's breaking down your night vision. (looks like "light", not turquoise) However, this applies to any color light, except red.
Red light at any level will preserve your night vision because the parts of your eye responsible for night vision are blind to red light. So you can use a relatively bright red light for navigation, looking at charts, seeing what's going on around you, etc, and when you shut it off you still have your low-light sensitivity.
Watch out, though. Too bright of a red light will leave afterimages on your retina that will interfere with your night vision since the afterimages in the red cones will overlap your night vision field of view. Use a somewhat dim red light if possible.
People tend to like green LED light because our Photopic (daylight) vision is more sensitive to green light and as a result green light appears brighter than any other LED light at the same power level. With green you get brighter light (almost double in the case of white vs. green KL1 modules), but no real color rendition capability. Plus consider the fact that a white LED light loses some of it's brightness because the phosphor takes the blue light of the led (yes, it's really a blue LED under there) and spreads out the spectral output across a larger number of frequencies - not as bright, but wider color spread. Sort of like going from a narrow hose nozzel to a wide spray - less pressure but larger area of coverage.