Blue mica is airbrushed onto the glass and fired to 1430 for 10 minutes. A plotter-cut stencil is applied and the circle for the moon is blasted. The glass is washed with the stencil in place (to remove the sandblasting residue) and then the gold mica is airbrushed on (about 10 coats). After the mica is dry, the stencil is carefully removed and the piece is fired to 1430 for 10 minutes again. To mix the micas, I put a teaspoon of mica powder in the airbrush jar, add Klyr-Fire until it covers the powder, then add a little isopropyl alcohol. Replace the cap and shake vigorously for a minute or so. I use an Aztec airbrush, but have also used a Badger with this mixing method, turquoise nozzle at 50 psi.
A photoresist stencil of the tree is applied to the tile and the edges are masked with masking tape. The tree is then sandblasted through the micas into the base glass. I use photoresist for the tree because of the detail. The tiles are then firepolished at 1450 for 10 minutes.
Both the plotter-cut stencil and the photoresist are computer-generated stencils. The graphics are done in Adobe Illustrator and the stencils are cut using a sign-graphics interface software. The photoresist is a photographic process. Start with a laser-printed graphic on vellum, then expose the photoresist material to UV light through the vellum. The photoresist material is washed under high pressure and dried. What is left is a polymer that is somewhat resistant to the sandblasting process. The material is glued to the glass prior to sandblasting.