The seals before Qin Dynasty, whether official or private, were called "seals". After Qin unified the six countries, it was stipulated that the emperor's seal was called "seal" and his subjects were only called "seal". In the Han dynasty, princes also called it "seal". Tang changed its name to Bao because it felt that "seal" was similar to "death" (some people said it was the same as "interest"). From the Tang Dynasty to the Qing Dynasty, the old system was followed, and "seal" and "treasure" were used together. Han general print called it "Zhang". After that, according to people's habits, seals have various names, such as "seal", "seal", "record", "Zhu Ji", "covenant", "seal", "pledge" and "seal". The seals in the pre-Qin and Qin and Han dynasties were mostly used as seals and bamboo slips, and the seals were stamped on the mud to prevent private disassembly for credit reporting. And the official seal symbolizes power. Bamboo slips on the back barrel are easily made of paper and silk, and the use of sealing mud is gradually abandoned. Zhu Caihong's seal is not only used for daily life, but also for calligraphy and painting inscriptions, so it has become a unique work of art in China. In ancient times, copper, silver, gold, jade and glass were used as printing materials, followed by teeth, horns, wood and crystals, and lithographs prevailed after the Yuan Dynasty.