Scum Trace of ink adhere to the non-image area of an offset plate due to its inability to tepel ink caused by poor desensitization or insufficient supply of damping solution.

• 柯式印刷的非印纹部分沾上墨的情况。是因为润湿液不足或消感处理不善,使非印纹部份不能拒墨所致。