Coloring Engraved Letters

There is a trick to make the stamped lettering on handguns stand out for photography so Colt's Patent Firearms Co. is very visible.  I think the technique involves spreading a thing layer of white paint across the surface then wiping away the surface layer.  Keep the gun flat until the paint or White Out dries.  When your photography session ends you use some solvent to clean out the letters you were trying to make more visible.

I ask because I am thinking a couple steps ahead about setting circles.  These are practically obsolete today with modern go-to controllers but they are a common component even on modern mounts and provide a backup navigation method.

My thought is to put a 4" diameter piece of black acetal on the rotating table (which still needs the Sherline CNC upgrade).  Write program to rotate the table one degree at a time, cut a 1" line, use the font library to scribe 0, then one degree rotation, cut a .25" line, ditto for 2, 3, 4.  Then a .5" line. Return to .25" lines until the next 10 degree line.  Continue around the circle.  Now apply a layer of white (or maybe even phosphorent to make it more visible in darkness) paint to the  surface.  Wipe off excess.  Allow paint in the scribed lines and numbers to dry.  Paint really does not stick to acetal.  Apply clear layer of polyurethane to hold the paint in place.  This seems like a solution.  

Why acetal, not carbon fiber?  There is no load on setting circles and they are about the same density as carbon fiber even a little lighter.  Aluminum is also a choice and paint will stick to it.