What is the historical origin of printing?

Printing is one of the four great inventions in ancient China. Its characteristics are convenient, flexible, time-saving and labor-saving, which creates conditions for the wide dissemination and exchange of knowledge. The techniques of seal cutting, rubbing and printing and dyeing in ancient China laid the foundation for the advent of printing. The development of printing in China experienced two stages: block printing and movable type printing, but it originated from seals in the pre-Qin period. Before the invention of printing, the spread of culture mainly depended on handwritten books. Handwriting is time-consuming and laborious, and it is easy to make mistakes and omissions, which hinders the development of culture and brings undue losses to the spread of culture. Seals and stone carvings provide direct experience enlightenment for printing, and the method of inking stone tablets with paper points out the direction for block printing. Seals existed in the pre-Qin period, generally only a few words, indicating names, official positions or institutions. All seals are engraved and reflected, and there is a difference between yin and yang. Wen Yin refers to characters or patterns with concave surfaces. Characters or patterns below the plane of the object are formed by printing or characterization of the stamp; Yang Wen refers to words or patterns with raised surfaces. Through die printing, knife carving, pen stacking and other means, characters and patterns higher than the plane of the object appear. Before paper appeared, official documents or letters were written on bamboo slips. After writing, tie it with a rope, seal it with sticky mud at the ligation place, and cover the seal with mud, which is called "mud seal". Ancient documents were carved with knives or painted on bamboo slips or wooden slips. When they are delivered, they are tied in a bucket with a certain shape, tied with a rope, filled with a piece of mud at the knotted place and sealed on the mud. After the appearance of paper, mud seal evolved into paper seal, which was covered at the joint of several official documents or the sealing of official documents paper bags. The invention of printing is the crystallization of the wisdom of our ancestors, and it has a long and arduous exploration process.