Originally Posted by DannyR
There is no advantage. Disadvantage is that the other colors are not as bright at green.
Now in total darkness contrasting colors may be easier to align, but one should not be shooting in total darkness because one cannot see or identify the target.
We all see what we see...
The human eye-brain could be said to be a unique perspective. For example, while white and black are spectroscopic opposites, most people see yellow/black, bright green/black and bright orange/black, as having the more striking contrast. That's an eye-brain thing.
Of the tritium lamps out there, green does appear to be the brightest to the human eye-brain, which is why the green lamp should go on the front sight, in a two-color set up.
Also regarding relative brightness, keep in mind that in the case of Meprolight and the Glock OEM Night Sights, the front lamp appears brighter than the rear lamps do--by design--even in an all-green set up..
While I've never felt handicapped by the all-green set up, my fifty-five year old diabetic eyes see the green/yellow set up just as well, and the gun's orientation is even more obvious to me.
I am, of course, talking low light here, not total darkness, which would render aiming by sights impossible… All things considered, I see no downside
to green/yellow lamps.