The surface of the tinplate is silvery white (or yellow) with metallic luster. Before printing color graphics, the surface needs to be printed white. Due to the limitation of ink coverage, it often needs to be printed 2-3 times white, and its whiteness can reach 75% . Whiteness is an important indicator of the quality of printed iron products. The white ink for printing iron has a good bonding force with the base oil. After repeated high-temperature baking, it will not yellow and resist high temperature steaming. The tinplate can be coated with a base oil to increase the adhesion to the tinplate and has a good combination with the white ink. Commonly used based oils are epoxy amine based, with light color, no yellowing, no aging after repeated baking, and good flexibility and impact resistance.