An actual Lite-Brite toy has a black background which utilizes blank spaces as "black", but does not have actual black pegs. For artistic and Guinness certification purposes (now an official record, see below), I was unable to leave blank spaces. What to do? Unused pegs were painted black with several layers of a special glossy paint made specifically for plastics. The result is a strong-bonded paint that doesn't chip or flake in the slightest.
The pegs are fixed to the "canvas" with 8 layers of glue. Not just any glue, but non-fogging cyano-acrylate (the most expensive and hard-to-find of the super glues). This non-fogging glue was chosen for its unequaled bonding strength and the fact that it wouldn't discolor the pegs, inhibiting light transmission.