| CTP technology has been paid more attention, for its development and application. The purpose of this paper is to obtain the main quality control parameters of plate-making and printing workflow by analyzing offset printing based on CTP digital workflow.In this paper, a fuzzy evaluation model of printing quality is established by using the fuzzy evaluation method and AHP, which is based on the designed plate-making testing file. An intersecting experiment is designed, which is about quality control parameters in plate-making workflow. The gray balance data of dot area coverage of cyan, magenta and yellow are obtained. Curves are founded by using regression analysis methord, which reflects the relation of gray densities and dot area coverages of cyan, magenta and yellow. A method has been given to correct the parameter"n"in Yule-Nielsen formula, which uses the combination of chroma method and density method. The"END"curves are founded. The disciplinarians of dot gain have been analyzed and the dot gain curves and dot gain compensation curves have been established by using regression analysis methord.The established parameters in this paper for laser power, developing temperature, developing speed and brush speed in plate-making workflow are 13W, 25℃, 75cm/s and 100rpm. The correlation coefficients of regression expressions of dot area coverage for cyan, magenta and yellow are 0.9993, 0.9997 and 0.9995; all of them are greater than the critical value which is 0.911. After corrected, the parameter of"n"in Yule-Nielsen formula is 3.142. Compared to the designed dot area coverages of cyan, the largest, least and equal errors are 1.9977%, 0.0011% and 0.8575%. The correlation coefficients of regression expressions of cyan, magenta, yellow and black dot gain are 0.9912, 0.9866, 0.9874 and 0.9927; all of them are greater than the critical value which is 0.546.The production of this paper is worthful for the spreed of CTP technology in national printing industry.
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