With the increasing maturity and the rapid development of CTP technology, as well as the declining of price, CTP technology has been more and more welcomed by the majority of printing practitioners, usage of CTP plates have the potential trend to catch up with the traditional PS plate. The overall requirements of the printing plate is very high, especially the current CTP plate is mostly used for high-grade color printing plate, to ensure the quality of the aluminium plate, the plate based apparent quality is the premise