The color of printing image needs to be transformed among different equipments in copy system, and that how to get the dot area of each primary color (namely each separate plate) is difficult in the color printing .

• 印刷图像的颜色在复制系统中，需要在各种不同的设备之间进行传递，而彩色复制的一个难点，就是如何确定各组分油墨(即各色版)的网点覆盖率。