The technology, principle and characteristics of color overprinting in the Northern Song Dynasty, and its advantages and disadvantages compared with block printing and or movable type printing.

In the color overprinter technology of the Northern Song Dynasty, the pigments used are traditional plant dyes or mineral pigments, rather than chemically synthesized pigments. One is to carve each color separately and then overprint one by one. The other is to brush different colors on a printing plate and print at one time. Prominent examples are the paper money "Zhu Mo Cuo" printed by Sichuan people in the early Northern Song Dynasty, and the painting "Dong Fangshuo stole peaches" found in Xi 'an forest of steles, which was overprinted with thick ink, light ink and light green.

Its principle is to carve the colors in the manuscript into plates with different shades, and then overprint them one by one.

Color overprinting includes dragon and phoenix, flowers and trees, utensils and other patterns, as well as historical stories, people's deeds and other pictures, such as Zhuge Liang's Fan commanding the three armies, Yao Shun's hanging clothes to rule the world, etc., which are beautiful and generous, set each other off and have high artistic value. But the printing process is also very complicated. It not only needs to be printed twice, but also needs accurate color matching, which correspondingly increases the cost of the book.