The composition and operation principle of digital proofing

In recent years, with the development of computer-to-plate technology, the digital field of printing and publishing has attracted attention. People have turned their attention to converting laser-illuminated output films to directly outputting plates, thereby reducing the number of processes and making printing quality better than before. Has greatly improved. As we all know, the cost of computer-to-plate supplies is high, and it is not possible to wait for the printing plate to go out and proof. Therefore, digital proofing must be used before the plates are exported.

1 The composition of digital proofing

Digital proofing is a comprehensive application of computer technology, color proofing technology, and color management technology.

1) Digital Proofing Software

At present, there are many color proofing color management systems in China, such as Best Color RIP, Color Tuner RIP, Explosion Color RIP, Founder Century RIP+ Founder CMS and so on. Most of these proofing systems use three color management techniques to simulate printed color effects. The Best Color RIP color management system uses internationally-accepted ICC color management technology to perform automated simulations of printed colors. The idea of ​​Color Tuner RIP color management system is to combine with Epson's Microdot technology to establish a new standard for color management and digital proofing system. It not only relies solely on the color correction technology based on ICC, but also combines its own The tone adjustment concept provides the user with FineTuning, an overall tonal adjustment and control tool with a good user interface. You can handle both spot colors and background colors. The StarProf Digital Proofing System uses a density meter and incorporates 150 color patches for visual correction to achieve consistency with the print results.

2) Digital Proofing Hardware - Printer

As we all know, there are many kinds of printers, and their main imaging technologies include laser, thermal sublimation, thermal transfer, and inkjet. At present, more digital proofing devices are used in EPSON, HP, and AGFA series products. Their common features are fast print speed, stable color, rich ink layer, and delicate colors. The six-color color matching system is generally used to add light blue and light magenta inks. The inkjet printing system ejects ink onto paper to form an image. There are two kinds of principles: one is a piezoelectric crystal type, and the other is a thermal foaming type. EPSON, AGFA series printers use piezoelectric inkjet printing technology, do not require preheating, small droplets, delicate screen, but the use of long intervals, the nozzle is easy to plug. The latest product EPSON 1000 series (1120mm wide) large-format inkjet printer can automatically clean the ink head at a time, which can better solve the quality and speed problems. Generally, it takes only a few minutes to print proofs.

Sublimation technology's proofing system uses a print head containing thousands of heating elements and a color strip containing CMYK colors for proofing. The proofing head can produce 256 different degrees of heat, allowing the solid pigment to sublimate into vapor and solidify on the medium. The center of each point is darker and the edge part is lighter in color. The four colors are printed together and become one. Continuously tuned image.

2 Principles of Digital Proofing

Digital proofing is essentially an application system composed of digital color management system software and professional color printers. The system uses color management software for color management, using this technology to output color samples on a computer-made layout before the output of the film or plate, checking the effect of the production, and has the effect of very close to the traditional proofing Customers sign as a print.

Digital proofing technology mainly through these aspects to achieve consistency with the traditional proofing methods. On the one hand, a color management system, also called CMS, is mainly used to measure the color standard of standard document color blocks and digital proofing devices for printing, so as to measure the data in the respective ICC format, and then calculate the color management system to establish The characteristic standard file profile required for digital proofing. This file is equivalent to a conversion formula, through which you can convert the digital proofing device and the color characteristics to simulate the color characteristics of the print, so that the digital proofing can be consistent with the printed color. On the other hand, the characteristics of color inkjet proofing need to be color managed so that the color reproduction of the proofer is close to the color gamut of the print.

Digital proofing can be divided into pre-RIP proofing and RIP proofing, depending on the type of data accepted. Before RIP proofing, the digital proof management software accepts the PS, PDF, and TIFF data before RIP, and interprets the files according to the RIP of the digital proofing system. After RIP proofing, it means that the digital proof management software directly accepts data from other systems' RIPs and then directly processes the proofing. The output device mainly uses two large-format inkjet printers, EPSON and HP, with an output resolution of up to 2880 dpi. EP SON's STYLUS PRO series 5000, 7000, 9000, 10000, HP's De signjet5000, etc. have multi-jet, micro-piezoelectric, 6-color ink and other advanced technologies, can achieve speed, color and stability of the unity.

3 Advantages of Digital Proofing

Whenever we mention the effect of digital proofing, which is invariably compared with the traditional proofing, the following brief talk about the advantages of digital proofing.

1) Digital proofing is faster than traditional proofing. The main models on the market today are HP, EPSON, AGFA, ROLAND and other brands. The printing format of these devices is large, and it takes only a few minutes to print the facing format. Traditional proofing is limited by various techniques such as filming, artificial spelling, printing, and proofing. It takes at least a few hours to play a proof sheet, and you can see proofs with a digital proof for up to half an hour.

2) Digital proofing quality is stable, and digital proofing has absolute advantages. Because the traditional proofer is artificially inked and pressure adjusted, the effect is very unstable, and it is greatly affected by temperature and humidity. As we all know, the same color separation film, respectively, to take proofs, the results will have different results. Digital proofing is not affected by environmental, technological, and human factors. The proofs and proofs can be kept exactly the same. Analog printing density, chromaticity, dot gain rate, printing plate characteristics and other factors are accurate.

3) Digital proofing system has less investment and high efficiency.

4) Good color reproduction capability. Most of the digital proofing machines on the market today are able to express richer color gamuts than printing inks. The rich color gamut coupled with the cooperation of good color management software, digital proofing can not only simulate other production effects, such as screen printing, digital printing, inkjet posters, and even simulate the performance on high-speed rotary machines. Satisfy the need for increasingly diversified output in the market.

5) Digital proofing can be synchronized at the same time as completing electronic documents, shortening the platemaking cycle. And can check the printing effect of electronic documents in various processes before printing, and provide more convenience for creativity, design, and modification. (Wen/ç¿Ÿqin)