I made this using the porcelain that Bridget Harper formulated for us. One thing that I discovered about this clay is that it does not like to be thick. I made a set of twelve small trays like this (only smaller) using the same technique (slab rolled, then formed inside a styrofoam meat tray). All but three of the small trays I made got cracked and split apart in the bisque firing.
Knowing that this tray had a large likelyhood of breaking in the kiln, I decided not to spend too much time on the cobalt design. I wanted to try it out. This is Kurt Weiser’s own cobalt formula. I’ve done cobalt on porcelain so often, I daresay it’s my trademark. This worked a lot better than the plain cobalt stains that I’ve used in the past. It didn’t fade nearly as much. Of course, getting the correct amount of overglaze is, well, there’s an art to it.