Some understanding of digital proofing

Proofing is used as a link between prepress and printing. It is not only checking the quality of the work of plate-making and proofreaders. And provide the basis and standard for the printing process, but also an important means of quality management in the production process. As a post-process of plate making. It is the reproduction process of image synthesis. It is the inspection 2 of the plate making effect as a pre-printing process. It is a trial production of analog printing, seeking the best conditions for formal printing and providing ink standards. A qualified proof can be used for analog output with a color separation film in the traditional way, and can also be output on a digital proofing device. That is to say; proofing can be divided into two kinds of analog proofing and digital proofing output. The fundamental difference between these two proofing methods is whether there is a traditional film output. With the development of pre-press digitalization and network technology, the digital process flow of pre-press “Yuan film” has begun to enter the pre-press field as a living force, and the proofing technology is undergoing a new digital revolution. First, the characteristics of digital proofing The so-called digital proofing is the digital proofing technology in the electronic excavation will electronic manuscripts processed directly after the digital output. It adopts a digital method to directly output the proof with a large-scale printer, which is used to replace the lengthy technological processes such as film in simulation proofing and printing. In the wave of digital rushing to face. The printing industry has high hopes for digital proofing. Industry experts believe that rapid and stable have become the two major advantages of digital proofing. Mainly reflected in: First, good reducibility, color stability. As the artificial proofing is mainly used for manual ink pressure and adjustment pressure; so the effect can not remain stable, no digital proofing is the use of all-digital process flow, thus avoiding the uncertainty of the human factor in the traditional proofing. Second; proofing speed; save time. Suitable for short-run printing. Print a high-quality facing sample proof and digital proofing is completed within 20 minutes. Analog proofing takes 30-40 minutes. Thirdly, there are few intermediate links and the use of film is eliminated. On the one hand, it reduces the printing and printing processes in the traditional proofing process. On the other hand, it also caters to the development trend of green printing and is conducive to environmental protection. Fourth, since all the entire process flow is digitalized, it is easy to use and easy to operate. Fifth, remote digital proofing can be achieved. Due to the use and development of network technology, digital files are delivered to remote sites, and proofing equipment is used for digital proofing so as to provide users with digital proofs. This remote digital proofing breaks the limitations of time and space. Simple and practical. Of course, digital proofing is in full time to show its elegant style; its shortcomings have also been revealed. Its shortcomings are mainly reflected in: First, although the development of digital proofing technology is becoming more and more mature. However, the digital proofing process is not yet very mature; in particular, digital proofing equipment lacks uniform standards; it is difficult for operators and customers to adapt. Secondly, because some digital proofing uses FM outlets, the operating technology of this outlet is more complicated than before. This is difficult for industry insiders who are used to AM sites to adapt. Third, the application scope of digital proofing is not universal, and it cannot meet the requirements for special color proofing such as hot stamping and hot stamping. Traditional proofing can easily be resolved at this point. Fourth, consumables problems are more prominent. Because digital proofing requires the use of special paper, the first is the increase in printing costs, and the second is the impact on the credibility of proofs. Fifth, the matching of management software for digital proofing with matching equipment such as printers, photo-setters, etc. is still not compatible with the situation. Therefore, as far as the current status of digital proofing is concerned, the general popularity of digital proofing is slow, and the original cost of consumables, etc., requires a traditional analog proof if the requirements for the live source cycle are not tight. Looking at the development of the printing industry, from the perspective of foreign countries, the advanced countries have started to popularize and popularize digital proofing. Some developing countries have only just begun to use; from the domestic situation, digital proofing technology has been widely used in gravure printing, but The development of offset printing is still in its infancy. At present, the popularization of digital proofing technology in Guangzhou, Shenzhen and other places is at the leading level in China. In today's digital proofing and analog sampling coexistence, although the characteristics of digital proofing has become clear, there are still some areas that need improvement in development and application. Therefore, comprehensive promotion still needs a process. From the point of view of technological development, digital proofing technology eliminates the interference of human factors and other external factors, greatly improves the reliability and stability of proofing output, and shortens the technological process as much as possible. With digital proofing, samples can be modified at any time. Theoretically, taxes can reduce costs. With the popularization and promotion of digital proofing technology, it can completely solve many problems in the long proof production period, unstable proof quality, and high cost of analog proofing, thus triggering another digital revolution in the printing field. It can be foreseen that digital proofing is a general trend to replace analog proofing. Second, digital proofing technology Digital proofing technology is becoming an integral part of the digital printing line. Digital proofing technology is mainly divided into four types: digital semi-continuous dot network technology; continuous tone inkjet technology; dye sublimation technology (Dye-Sublimation) and revamped inkjet technology (dro-On-Demand referred to as DODL). In addition, other digital proofing technologies such as variable point transfer laser technology and hot wax technology have also been applied in digital proofing systems. However, the specific application is not extensive. The following briefly describes four common digital proofing techniques. 1. Digital semi-continuous tuning technology This technique uses a thermal laser to form a proofing sample by using CMYK four dyes to form images on sub-sheets and then superimposing each sub-sheet together. This technique simulates dot gain patterns and dot angles in printing as well as other printing characteristics; inks are provided for WOP colors (sometimes GRACol and Eurocolor) by using special sub-sheets. The use of laser imaging digital half-tone dot proofers can not only compete with similar proofs in quality, but also surpass it. However, because the color values ​​such as hue, saturation, and aperture degree on the sub-sheet are relatively fixed, it is difficult to transmit the color point using the equipment of the car continuous adjustment technology, which is a fatal disadvantage of the application of the technology. Manufacturers using this technology are currently working hard to develop a sub-laminate production line for ordinary mercury color, but the use of the effect is not satisfactory. The Kodak company is looking for a breakthrough in the other direction. The "color spectrum" created by the company's Approval can be copied and output by using the CMYK on-screen color. 2. Inkjet Printing Technology This technology is one of the middle and upper gear technologies in the digital proofing market. It is also used for contrast proofing and content proofing. This technique is primarily used to produce images by delivering a continuous stream of ink to a printhead, which is diverted to a substrate that requires pigment. Since the ink can be synthesized in various colors, the inkjet proofer is more flexible in creating color points than the digital semi-continuous tone proofer. Digital proofing machines using this technique are slower than dye sublimation proofers in proofing speed, but the quality and color accuracy obtained is higher than that of a dye sublimation proofer. The disadvantages of this technology are: First, the printability of color needs further improvement; second, the ink flow sometimes cannot be smooth. 3. Dye Sublimation Technology This technology is also one of the middle and upper technologies in the digital proofing market. It is also used for contrast proofing and content proofing. The dye sublimation proofer transfers the pigment to the substrate by thermocompression bonding and produces images through a series of processes. Print proofs of the same web size; the proof rate of a dye sublimation proofer with a good quality and an inkjet proofer is almost the same. The disadvantages of digital proofing equipment with this technology are: First, special substrates are needed, which increases the price of a single page; second, coarse proofing cannot be done on general paper. 4. Can be revised version of inkjet technology can be revised version of inkjet technology is one of the market's lower-end technology, it is transferred from the office printing to proofing market quite DOD inkjet system. It has many different models, such as thermal proofing, pressure proofing, and bubble jet proofing, all of which share the same ink path rather than continuous oil jets. Some of these devices are not stable enough for performance, they cannot be transmitted by branches, and the printing speed is slow. Currently, DOD inkjet technology is improving and perfecting color processing and color rendering so as to better imitate actual printing color and printing environment. Third, digital proofing equipment For digital proofing manufacturers, the biggest technical problem lies in whether it can provide similar sites and Cromain and Matchprint proofing equipment, because this is the docking point of analog proofing technology and digital proofing technology. In the early days of the development of digital proofing equipment, 3M's Digital Matchprint and Kodak's Approval Digital proofing T-type system respectively introduced two kinds of rich tone dot digital proofing equipment to the market. Because the two devices use the method of “dithering” or “random continuous screen” to simulate halftone dots, the levels and colors printed out are inconsistent with the actual printing process, thus hindering the development of digital proofing. Lris Graphics has been developing and progressing for nearly two decades. The lris printer introduced as a high-end prepress proofing device has attracted the attention of the pioneers of digital high-grade proofing with its fine continuous output capability, and has finally developed a digital high-grade proofing market. Here are some popular digital proofing devices in the market. 1. IMATION RAINBO Imation Rainbow introduces the world's first accurate color desktop proofing device, which is one of the outstanding members of today's large family of proofing equipment. There are two main models in Rainbow's market: One is the 2730 model, which only updates the original organic model. Another newly introduced 2740 model has a print area of ​​460x310mm, including bleeding lines, which is twice as much as A4 pages. The Rainbow 274O can also print proofs with metallic and white ink effects, which provides new applications for packaging printing proofing and high-quality quality proofing. Rainbow series proofer has excellent color correction software system, it can use professional Mac machine for eight color separation. Eight-color printing effect is achieved through ink roller contact during the printing process. Like most dye sublimation proofers, the Rainbow2 series can only simulate one type of printer, but color lookup tables and dot gains can be used to better simulate print images. Recently, the number of color management software for this series of proofing equipment has increased. The Gretag color ladder, but the color accuracy obtained is not very accurate, and its effect has not reached a satisfactory level. 2. IRIS REALIST The Lris Realist series proofer of Scitex, which dominates the digital proofing market, has been recognized by the market and customers after years of development and hard work. Scitex company has been committed to some basic research to maintain its brand position in the digital product market. Based on this, it has made great efforts to develop high-end digital proofers and large-format digital proofers as its main target. At present, the company's high-end digital printer market has accounted for more than 20% of the market share. Now the term "lris" is used to describe high-end digital proofing. Scitex's new printer is based on the lris Realist, and the Realist 5013 and Realist 5030 models are introduced; the Realist 5013 has an output size of 533 x 355 mm; the Realist 5030 can achieve 533×762mm. Both machines can use Adobe CPSI Rips based on a PC or Mac or Scitex's own Ripro server. Lris Graphics currently focuses on the development of GPrint digital printers and uses it as an updated replacement for the earlier 3047 printers. Unlike 3047, GPrint is designed specifically for the high-end printing market, and many details have been modified at the request of lris users. The main improvements are: The position of the print head - it will allow the use of thicker print substrates. Two potential competitors faced by LRIS's large format printers are: Epson's MicroPiezo print head technology; Roland's Hi-Fi Jet printer and Minaki's JV2-130 printer. Lris’s most powerful competitor in the high-end digital proofing market is Color Span’s Giclee PrintMakerFA proofer, which uses eight colors (CMYK plus light, medium and light blue, and four colors) to proof , on a 35.5 x 47.5 inch web