Very impressive results Ed.
I have experimented with laser engraving white paint on aluminum in the past with very good results. The best paint I found to get the best results sells at Family Dollar for $1 a rattle can. The brand is Red Devil.
I purchased some 8X10 .08" Brown Chipboard off Amazon and Thunderbolt shipped Brown/Gray by mistake. It laser engraves OK, but not as good as the Brown IMO.