Lead Glaze is one of the four traditional techniques of glazing earthenware. The other glazes are tin, salt and feldspathic. Romans and the Chinese used lead glaze to decorate ceramic. The sancai or three colored pottery of Tang dynasty of China arose from green-glazed (lead glaze) pottery of Han dynasty. It was prevalent in medieval Europe and colonial America. But modern research has proved that lead is toxic and lead glaze should not be brought into contact with food.