Turn down the ink viscosity, the color becomes lighter, on the contrary, the color becomes darker. However, do not blindly reduce the viscosity to change the color, otherwise it will cause other problems, such as water lines, dull color, etc. In color matching, we should master the variation bias of viscosity of different colors in order to make better use of viscosity. For example, when the primary color yellow has high viscosity, it tends to be red, while when the viscosity is small, it will show green; The green viscosity is larger than the blue phase, and the yellow phase appears when the viscosity is small.