Seal introduction: the seal is printed on the document as stationery, indicating identity or signature. Generally, seals should be dyed with pigments before printing. Those that are not stained with pigment and will appear concave and convex after being printed on a flat surface are called steel seals, and some are wax prints printed on wax or wax paint or envelopes. Made of jade, metal, wood, stone, etc. Chinese seal is one of the representatives of Han traditional culture.