Red oxide on a plain ceramic bowl

Very impressed with that brush. Apply heated wax (like candle wax) to a bowl. When it dries, it will resist the glaze (paint) and the glaze will simply not stick to it. In order to finish a piece of pottery, you must fire it in a kiln at very high temperatures. When you do, the wax simply melts into the bowl (keeping the glaze from sticking) and the glaze is heat tested and becomes hard and the finished color.