The technique of making three papers in the lead mountain has been passed down for thousands of years. It is an ancient technique that was sublimated along with other bamboo paper crafts in the middle Tang Dynasty. In the "Tiangong Kaiwu" of Song Yingxing in the Ming Dynasty, the status of the papermaking of the lead mountain was recorded in many places, and the four papers of the lead mountain were highly praised. Even the four papers are made from the tender bamboos before and after the summer. They need to be exposed to the sun and rain for several months, naturally bleached, and the production process is complicated. All the experience is based on manual operation and the production cycle lasts for one year. Even the four papers have the reputation of "life paper millennium". After the Yuan Dynasty, many of China's great masterpieces and famous books were printed on four papers. Many calligraphy, prints, and extensions were also handed down. In the Ming and Qing Dynasties, if the literati and the famous painters of calligraphy and painting can get the authenticity of the Emperor's royal master, even the four papers are a great honor.