added by archaeologs Sgraffito ware is glazed vessels prepared first by incising decoration in the surface and then adding paint in the incisions prior to the application of glaze. There is a contrast between the brightly colored decoration and the overall color of the glazed vessel. Byzantine sgraffito wares date to the 11th-12th centuries in western Europe. It was not until the 16th-17th centuries that the technique was established in northern Europe. Sgraffito ware was produced by Islamic potters and became common throughout the Middle East. The 18th-century scratch blue class of English white stoneware is decorated with sgraffito patterns. Sgraffito ware was produced as early as 1735 by German settlers in colonial America. Sgraffito is also a form of fresco painting for exterior walls, done in Europe since the Middle Ages. A rough plaster undercoat is followed by thin plaster layers, each stained with a different color. These coats are covered by a fine-grain mortar finishing surface. The plaster is then engraved with knives and gouges at different levels to reveal the various colored layers beneath. It is also a glass-decorating technique.