Tang tri-color pottery, commonly referred to as Tang Sancai, is a type of low-temperature glazed pottery. It is made using white clay as the body and minerals containing copper, iron, cobalt, manganese, and other elements as coloring agents for the glaze. A significant amount of lead slag and lead ash is added to the glaze as a flux, and the pottery is fired at approximately 800°C. The glaze exhibits a variety of colors, including deep green, light green, emerald green, blue, yellow, white, ochre, and brown, earning it the name “Tang Sancai” (Tang tri-color). However, it is actually a multi-colored pottery. Among tri-color pottery pieces, some display only one of these colors, referred to as monochrome or single-color; those with two colors are called bicolor, while those with more than two colors are termed tri-color.
The glaze of Tang tri-color pottery contains a large amount of lead. Lead oxide acts as a flux, lowering the melting temperature of the glaze. During kiln firing, various metal oxide colorants dissolve into the lead glaze, spreading and flowing in all directions, allowing the colors to blend and form a brilliantly mottled, lustrous glaze. Another function of lead is to enhance the brightness of the glaze surface, making the colors even more vibrant.
