In the drying process, light quick-drying offset inks based on oxidation conjunctival type drying. There is a fixed stage before offset printing ink dry, oxidative polymerization is an exothermic reaction, it will release a lot of heat when drying is too fast, if heat dissipation is slow, thermolabile pigments will change color, such as golden color inks become darken.

If the sheet piling too much during printing, the middle of the ink sheet will take place oxidative polymerization, it will release heat, the heat is not easy to distribute, the temperature is too high to lead to change color.