Sgraffito is the word of the day. Sgraffito (an Italian word meaning “to scratch”) is a decorating pottery technique produced by applying color to clay then scratching off parts of the clay when it is leather hard, creating contrasting images, patterns, and texture that reveal the clay color underneath. This technique has been around since around the 15 century.
So for this project, we follow in the footsteps of potters have been doing for centuries, minus the kilns, to make sgraffito bowls. I used store-bought, Activa Plus Self Hardening Clay. It's a really nice clay; it's fine, moist, malleable, firm (but not hard on your hands). Keep moist by spraying water. I find it similar in texture and behavior as ceramic earthenware clay, ideal for sgraffito work. You need some kind of lightweight paint to go over clay. I used Imagine's Tsukineko’s All-Purpose Ink. A light, but highly pigmented ink, perfect for this project. Get detailed images and instruction at Imagine's Blog.
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