Oftentimes painting in China will feature an assortment of bright stamps. This includes the stamp of the original artist, but there are also stamps from owners of the painting, people who have restored it, wealthy nobles who have viewed it, and even occasionally a stamp from an art critic that approves of the piece.
The idea of stamping art runs against Western values, and many Western art historians recoil at the idea of putting a mark on a precious painting. No one would stamp a Monet, for instance. However, in China, where history and the past is valued to a far deeper extent than in the West, these stamps add to the complex historical background of the piece. It adds to the richness of the piece to notice that a certain emperor once looked at the same image with his own eyes.
Autumn Colors on the Ch'iao and Hua Mountains, Zhao Mengfu