Here is another sample of how you can use the fact that the luminescent coating fires off to your advantage. For this design, Melissa cut 3 curvy strips of Papyros Paper and glued them with a bit of white glue to the luminescent white glass. Than she added the little pieces of blue and green and fired the piece “decor side” up at 1410° F target temperature for 10 minutes. 

The none protected white glass lost all the luminescent, while the covered parts remained fully coated.