Quoted from benheck:The best way would be to screen print the underside as it would be super fast one color and not eat up flatbed printer time.
I also like how deeproot has it painted white to bounce more light.
Why would you want it to bounce more light? The lights are pointing up. If excess light escapes, then it would make non lit inserts faintly light
I don’t think that’s a serious concern, I just don’t see the benefit of bouncing light vs potential downsides.
Manufacturers used to paint them all a flat gray. I assume that was to cheaply absorb light pollution instead of faintly lighting things? Never heard a good answer for why that was.