All we did was spray it with Krylon gray primer, then paint with regular craft acrylics, and then finish off the stonework with a dry brushing of Unbleached Titanium acrylic by Liquitex. I'm really happy with the Ultimaker Gray/Silver PLA, we've been testing a lot of filaments by various manufactures and the gray/silver is holding the very tiny details far better than anything else we've tried.