and another thing.....
I am a student of safety, so thought I'd comment.
back in the late 70's when working at an AMO/FBO, as part of a 50-hour, we'd always re-paint the back flat black. After wiping bugs off 100 times, the flat black is no longer flat, and starts to show up when flying away from a sunset.
the painted tips were always refreshed...the contrast between a grey prop and white tip doesn't make the best 'ring' visible.....it's better to use black and white next to each other (or black & yellow if possible).
For a time, there were theories about alternating the black bar on one tip with the white bar on the other, hoping to get a 'strobe' effect, but I think in daylight, this is a fallacy!...it really just diminishes the nice sharp 'ring' look.
Guys with something like a pusher amphib would be wise to paint both sides with conspicuous bars.
Guys with the beautiful custom striping & arcing coloured tips and nickel leading edges on certain composite props, might want to consider incorporating something more contrasting, that produces a visible arc when viewed from the front.
just sayin' YMMV, $.02 etc.