Research And Development On Printing Simulation System Based On Digital Prepress Process

The demands on refinement of printing products become more and more eilig, so comprehensive study on root of generation errors and control methods in the printing processes, and enhancement on printing quality have become a research hotspot in the industry. Since the world went into the digital age, a series of prepress processing methods and systems has appeared. Digital prepress process exists many systematic errors, and some errors can be compensated and controlled by parameters adjustment, some are impossible or limited. Developments on printing simulation system have positive methodological significance for analysis of digital prepress workflow errors, latter compensation and control. This paper develops and implements the simulation system with basic RIP functions based on study of digital prepress workflow. This system can not only implement color-separation and screening, but also simulates the printing under ideal conditions, and makes a general prediction for printing results. Main research work of this paper and obtained conclusions are as follow:1) Analyzed the development of prepress workflow, and studied on the digital prepress systems, particular data process-flow in RIP system. On this basis, the modules were be decomposed and functions were be analyzed. This system has five modules including read and display digital image, RIP processing, printing simulation and preview, analysis of color-difference, system-configure.2) Analyzed and studied color space conversion methods. Chose and confirmed color space conversion methods used in the system. Researched and analyzed color space conversion methods from CMYK to RGB, and selected Neugebauer equation as core algorithm with stronger theory and higher operability.3) Based on Neugebauer equation with the percentage of actual color element area, implemented function module of printing simulation by programming. Based on digital information of color-separation images after screening, superposed different plate's data directly, and implemented system function of preview. User can preview the printing simulation efforts selectively by stages. 4) Researched and analyzed common evaluation methods of color-difference, and used color-difference equations of CIE1976, CIE1994, CIE2000 and CMC(l:c) respectively.5) Researched and analyzed common image formats in digital prepress system, and identified data formats and storage methods in each process. Implemented the function to read, modify and display the image.6) Programmed with GUI in Matlab, and designed the man-machine interface. The interface is easy to use, and operator can analyze and preview the image which will be printed according to demands.