Digital Modular Process Analysis of Prepress (II)

2.2.2 Color separation processing (RIP)

There are tens of thousands of color numbers on the color image screen, but high-end printing uses the four-color + spot color printing method. For ordinary manuscripts that do not have spot color printing requirements, the manuscript is first color-decomposed and divided into four color plates of blue (c), magenta (M), yellow (Y), and black (K), and then printed for color synthesis. If there is a request for spot color printing, this part of the image needs to be divided into excellent editions, and finally printed in combination with CMYK four colors. Due to the development of digital prepress technology, manuscript colors can now be separated, sampled, and converted into digital information by some software. The digital information can then be decomposed into blue (c), magenta (M), and yellow by computer through mathematical calculations. (Y), Black (K) Four-color information and spot color information, the color separation of the original document is saved as a corresponding format, the film is output directly on the laser image-setter, and finally made into various color printing plates. This is called the Raster Image Processor (Raster Image Processor) in the prepress field, see Figure 3.

In the printing field, RIP technology has become the core of the digital workflow. The RIP operation method can be divided into two kinds: NORM method and ROOM method.

1) NORM—Normalise once Render Many means that all the data described in the Postscript language command in the file is calculated first and then page by page. This method can calculate files in PDF format or other formats, laying the foundation for future operations (such as defining trapping, OPl, imposition, etc.).

2) ROOM - Render once Out Many means that all the data described in the Postscript language command in the file is first computed and colored, and then output page by page. The main advantage of ROOM is that files have been colored so that the consistency of output on different devices can be guaranteed.

2.2.3 Laser Film Output and Proofing

After the color separation processing, the generated file needs to be saved as a file format that can be recognized by the laser imagesetter (such as EPS format). After transferring such files to the digital image prepress center (laser imagesetter) through the network, relevant documents can be set according to the printing process requirements and the film can be output directly. The film output from the laser imagesetter is sent to the plate making room for printing SUY!E, which can then be proofed on the machine. If there are image problems in the proofing process, file amendments should be made in time and RIP and its follow-up operations resumed.

3 Digital Prepress Technology in Packaging Applications

The implementation of digital prepress operations requires corresponding high-end hardware and software equipment to support them. SUYqZ has a relatively high cost, so at present, it is mainly used for high-quality stickers, packaging materials, color books, magazines, advertising posters and other high-grade prints. The printing process.

In recent years, self-adhesive label packaging materials have developed rapidly in the foreign packaging industry, and their application in China has become more and more widespread, with the development rate of about 10% to 20% per year. Compared with traditional labels, self-adhesive labels do not need to be glued, glued, drowned, or dyed, which can save labeling time and can be applied to various applications quickly and easily.

As the role of adhesive labels in the field of packaging materials has become increasingly prominent, merchants are paying more and more attention to their print quality. It can be said that printing quality has become an important indicator to measure the quality of self-adhesive labels. The digitization and intelligence of prepress processing technologies provide powerful technical support for accurately printing high resolution images in small areas. The application of digital prepress technology greatly shortens the printing cycle of adhesive labels, reduces manual operations, improves product quality, and increases the degree of automation. These changes have driven sticker manufacturers to provide customers with a full range of services that are shorter in cycle, lower in price, and higher in quality.

4 Conclusion

The rapid advance of digital technology and the widespread use of computers mark the arrival of the information age. In today's printing front-end field, there has been a change in the transformation. Under the conditions of new technology, rational allocation of resources and effective management and control of the prepress operation process is the key to improving the printing production efficiency, and it is also the fundamental of the printing enterprises in the new century to become bigger and stronger.

Yang Junshun, Ge Teng
(Shaanxi University of Science and Technology Source: Packaging Engineering, 2005, Issue 4