I painted both sights green with Bright Sights (works well, very expensive). Then I decided I wanted more contrast between the front sight and the rear sight and I wanted the front sight to be more prominent than the rear.
Went to Michael's craft store (A.C. Moore, Ben Franklin, etc. would also have this). Found 2 oz. bottles of acrylic craft paint in almost any imaginable color for $.89 each. Bought two different colors (enough paint for thousands of applications) Settled on the red (it is actually almost pink). It stands out well against most background colors.
Applied a couple of coats with a toothpick. I waited until the next day so the craft paint would be completely dry, then I applied an overcoat of two coats of my wife's clear nail polish. I also overcoated the Bright Sight green while was at it.
After two years of 24/7 carry the edges of the sights that rub against the holster are beginning to need a touch-up.
One thing I noticed is; the more the light is coming from behind (shining on the sights) they brighter they are and the more they stand out, the more the light is from the front the darker and less colorful are the sights. Also, the dimmer the light the less colorful and more black they look.
Bottom line… I find the bright colors help a lot under most conditions, and I like the painted sights much better than the black.