underglazing

thumb|Japanese porcelain Hirado ware paperweight with [[chrysanthemums and plum blossoms, underglaze blue and brown, 19th-century]] thumb|Dish with cypress, Turkey, İznik, , underglaze-painted stonepaste – Royal Ontario Museum – DSC04735

Underglaze is a method of decorating pottery in which painted decoration is applied to the surface before it is covered with a transparent ceramic glaze and fired in a kiln. Because the glaze subsequently covers it, such decoration is completely durable, and it also allows the production of pottery with a surface that has a uniform sheen. Underglaze decoration uses pigments derived from oxides which fuse with the glaze when the piece is fired in a kiln. It is also a cheaper method, as only a single firing is needed, whereas overglaze decoration requires a second firing at a lower temperature.