I used a laser cutter at TechShop, a phenomenal resource for artists, builders and craftspeople of all kinds. They have workshops in several US locations with tools and space for woodwork, metalwork, industrial sewing, electronics, arduino, and more.
[Note: Since I wrote this, TechShop filed for bankruptcy and has been reborn as TheShop.build. Same space, same apparatus. I haven’t been there yet but I plan to.]
Step 1: Engrave artwork from a digital file. I did mine backwards on the back of the glass so it would show through right way round from the front and the color would glow through.
Step 2: Apply paint or marker.
Step 3: Scrape off excess paint or marker.
Click here to see a short clip of the laser in action.