The surface of ceramic products is coated with a layer of glaze, and colored porcelain is glazed with a certain compound. Adding lead oxide will appear milky yellow, adding cadmium compound will appear red or yellow, adding antimony compound will appear white, adding chromium compound will appear green and vermilion.
After high temperature firing, although the toxicity of some heavy metals such as lead and cadmium will combine with other elements and disappear, if porcelain comes into direct contact with acidic drinks or food, it will dissolve again and pollute drinks and food. This poisonous food will cause poisoning once it enters the human body. Although pottery has no color, lead in glaze can sometimes poison people.
The origin of porcelain bowls
According to archaeological discoveries and historical records, the earliest porcelain bowls were primitive celadon products, which were used from Shang and Zhou Dynasties to the Spring and Autumn Period and the Warring States Period until today.
There are obvious differences in modeling, glaze color and decorative patterns of porcelain bowls in different periods. Before the Tang Dynasty, bowls were mostly straight and flat-bottomed, glazed to the end, and basically had no ornamentation.
The decorative technology of painted flowers was applied to bowls, which began in Changsha kiln in Tang Dynasty and transited to Cizhou kiln in Song Dynasty. Its inspiration comes from the blue and white flowers in Yuan Dynasty, and it really flourished in Ming Dynasty. The bowls of the Qing Dynasty are better than those of previous dynasties in every respect. The shape, glaze color and decorative pattern of the vessel are more abundant and diverse, and the craft is more exquisite and delicate. The royal bowl decorated with three colors and five colors is even more amazing.