I'm very new to ceramics and need help with underglaze and clear glaze compatibility. I use Duncan covercoat on bisque with a Colorobbia CLA3 non toxic clear glaze over it. The problem is, the color just doesn't come out right when I use this glaze. I have tried firing at higher temperatures, I have tried putting the covercoat on leather hard clay, firing, then dipping in clear glaze and firing again- nothing seems to work. The color doesn't come out. I have contacted both Duncan and Colorobbia, both seem to say that the two products should work just fine together. When I tried a different clear glaze (lead based) it seemed to work perfectly fine, the color comes out just right. The problem is I do not want to be using a lead based glaze as my pots are for dinnerware! Any suggestions or ideas would be greatly appreciated! Thanks!!