Specific phenomenon: field coverage is not good causes: NATURE: the field color is too light 1, first of all to check the ink coloring rate 2, printing full plate printing process is correct 3, the printing plate on blanket and blanket on paper pressure is not enough solution: The Essence: to improve the color block coloring rate 1, choose the ink with high coloring rate 2, can consider underpainting and multiple printing 3, check the printing plate, blanket thickness, increase the pressure