Also called dyeing and finishing. It is a kind of processing method, and it is also the general term for pretreatment, dyeing, printing, finishing, washing, etc.; the undergraduate dyeing and finishing major has now been merged into the light chemical engineering major; as early as the Neolithic age six to seven thousand years ago, Our ancestors were able to dye linen cloth red with hematite powder. The primitive tribes living in the Nuomuhong area of the Qaidam Basin in Qinghai can dye their wool into yellow, red, brown, blue and other colors, and weave woolen cloth with colorful stripes. During the Shang and Zhou dynasties, dyeing technology continued to improve. In the palace handicraft workshop, there are full-time officials "dyeing people" to "handle and dye the grass" to manage the dyeing production. The color dyed is also increasing. By the Han Dynasty, dyeing technology reached a very high level.