What does the seal of the book mean?

The characteristics of the times and the breath of the seal are the evidence to identify calligraphy and painting. The flavor of the times of seal can be seen from its shape, seal script, engraving method, texture, printing color and so on. In the Song Dynasty, few paintings and calligraphy works were stamped with the painter's own seal, and most painters did not stamp their own seals on their works. In the Song Dynasty, the materials of seals were mostly copper and jade, and a few were other materials. There are two kinds of printing colors: honey printing and watermark (a few mimeographs appeared in the late Southern Song Dynasty). The honey print is red and thick, and the watermark is weak. The seal script characters and engraving methods of Yuan Dynasty seals changed, and a round Zhu Wen seal appeared. Materials are wood, ivory, copper, jade and so on. And most of the printing colors are mimeographed and watermarked. Since Wang Mian began to use stone carvings in Yuan Dynasty, more and more people have used them. At the beginning of the Ming Dynasty, the seals of various stones were quite common, and the methods of seal cutting characters also had new changes. The stop stroke of each character of seal script is slightly thicker than the original stroke, but lighter and slightly yellow, which is somewhat different from the printing color of Yuan Dynasty. Most of the seals in the middle and late Ming Dynasty were stones, others were crystal, agate, copper and jade. Fonts include China ancient seal script and other forms. During this period, the printing colors were mostly oil paints and shades, and a few painters used watermarks. The characters of seal script used by painters and painters in the early Qing Dynasty did not change much, but the shapes and fonts of seal script tended to be diversified. In the middle and late Qing Dynasty, various kinds of seals and seal cutting appeared, such as Zhejiang School and Anhui School, and most of them took Shuowen Jiezi as the main body. The printing color comes from oil, and the watermark is no longer used.