Slip Inlay and Sgraffito - Hieroglyphs

Hieroglyphs applied with slip inlay - in greenware state

One of the many decorating techniques that I learned at the fabulous San Jose City College was Slip Inlay.  This was actually courtesy of the wonderful (and late) Julia Terr. She was a visiting artist at SJCC and enlightened our class with her techniques in throwing and decorating.  This included: goblets and pitchers, glazes and, of course, slip inlay.

I became fascinated by her methods and decided to explore some of her techniques in my own work.  I made some of my own style of goblets (as seen in the previous posting).  I also re-created the beautiful green glaze, which she supplied the recipe for (and which was also my first foray into glaze making).  And I explored slip inlay.  Of course at SJCC we were somewhat limited by the slips, having only black, white, blue and green.  However, here at UC Berkeley we are blessed to have a wide array of colored slips.  This includes metallic colored slips (which I prefer due to the sheen produced in Mid – High range firing) as well as those colored by stains. 

The image above shows greenware bowls, and one cup that have been decorated using the metallic slips: Cobalt Oxide, Manganese Dioxide, Red Iron Oxide, Black Copper Oxide, and Rutile Oxide.  Most of these bowls were thrown in Babu Porcelain and decorated with the Slip inlay method that I learned from Julia.  If you've never done it before this is how it is done:
1. use a needle or sgraffito tool to carve a pattern or image into the surface (pretty deep). 
2. Then fill it in with the slip with a large brush, you will need to apply multiple coats.  The slip is thick enough when you can no longer see the carved image through it. 
3. let it dry sufficiently, dry side of leather hard, almost bone dry.
4. Then scrape the slip off with a metal rib.  Some of the clay surface will come off too.  This is why the carving should be pretty deep.

On the last bowl I used the sgraffito method, with is even easier and can be used with slips, underglazes and glazes. I just painted a thick layer of the slip over the leather hard surface of the bowl.  Then used the sgraffito tool to draw and image into it, thereby carving away the slip and revealing the clay underneath.