Everest high fidelity printing technology with the

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"Everest" of printing quality: high fidelity printing technology (Part I)

high fidelity color printing technology began to enter the production workshop of printing enterprises from the laboratories of experts in the late 1990s. This has become a sign that the printing industry has begun to stride into a new era of color quality. The ability of high-speed computing and storage of modern computers and massive retrieval of software can help scientists further understand the characteristics of color, grasp the key technology of color reproduction, and correct the shortcomings of the original printing theory and technology. In this effort, experts have successfully studied high fidelity color separation technology, and established a complete set of high fidelity color printing technology in cooperation with production enterprises, which is convenient for practical application of printing enterprises. Today, the application of high fidelity color printing technology in printing enterprises is as convenient as the application of conventional four-color printing technology, and can greatly improve the printing quality

printing industry 4 The process of technical progress in cooperating with the Engineering Department of CNR r r & D center on the sound absorption and noise reduction project of high-speed rail

from the analysis of the original to the delivery of printed products to customers, the number of links and the complexity of process parameter regulation are difficult for outsiders to understand. However, when facing customers with high quality requirements, the quality of printed matter is always criticized and complained. The scenery copied by printing is always obviously different from the feeling of people actually observing the scenery in nature. Under the current conditions of conventional four-color printing technology, copying bright colors in paintings will become gray; The flexible light effect in photography works will become dull; Packaged prints can be easily copied by other enterprises and become identity certificates of fake and shoddy goods Enterprises and people who pursue printing quality may think about such questions. When can the limitations of printing color be broken through? Can the quality of printed matter get a new display in their own hands? The development of printing industry is closely related to the progress of social science and technology. From the development of printing technology, it can be seen that in the mid-15th century, Johannes Gutenberg invented a printing method of reusing metal movable type. In the 18th century, the development of optical technology and photosensitive materials helped print images to show the effect of photos, which made commercial publicity and the dissemination of scientific and technological knowledge fly. In the 19th century, the development of color science not only created color photography, but also helped the printing industry realize full-color reproduction of images by color filter color separation and contact screen addition. After entering the 20th century, the application of computer and laser technology has enabled the printing industry to have its own color electronic color separation and halftone addition technology. Since then, a key step in digital printing has been taken on the road of printing and reproducing the true colors of natural scenery. At the end of the 20th century, high fidelity color printing technology began to be applied in high-end printing enterprises, marking the beginning of a new era of printing technology. The main feature of high fidelity color printing technology is that more than four kinds of primary color inks participate in color separation, which expands the printing color gamut; The color separation algorithm ensures that the reproduction of color components and neutral gray components in the print is closest to the color characteristics of visual perception, and the print will present a new visual effect. Therefore, the printing industry has used the four-color separation technology for a hundred years, and has to retreat into the low-end application field because of its obvious defects. In the course of the development of printing technology, we will have the honor to experience the new and old technologies. The pace of history will not stop, just like exploring the emergence and development of the universe, the earth and mankind, many problems still perplexing us in printing technology also need to be constantly studied and solved. Today's printing industry not only reflects the brilliance of modern scientific and technological achievements, but also shows the wisdom and pursuit of printing people of all dynasties

characteristics of the new era of printing

today, color scientists all over the world continue to provide many valuable methods for color perception, measurement and reproduction, which makes it possible for us to think new about printing technology and quality, seek new methods and reach a new height. The complexity of process parameter regulation in printing enterprises is mostly related to color images. The process basis of conventional color image printing and reproduction is four-color separation. There are two questions worth thinking about this foundation. First, printing color images is actually copying the scene in the natural environment. The printing process cannot directly copy the real three-dimensional scenery onto the flat medium. The photographic equipment projects the scene onto the photosensitive material, continues to crack down on the "ground bar" or records it in the photoelectric converter, and then delivers it to the printing process as an original. An ideal manuscript should faithfully represent the shape, color and brightness characteristics of the actual scene

in order to make the printed image closer to the observation effect of the actual scene, we should understand the color characteristics of the original record and how it is different from the visual perception effect of the scene in the natural environment, which is particularly important to ensure the quality of high-end prints. For the description of the differences between the two and the analysis of their technical reasons, the author will express it in another article. It is mainly pointed out here that this problem is intentionally or unintentionally ignored in the conventional four-color printing process. This leads to the fact that the current four-color printing process customarily obtains CMYK data from the original scanning, regardless of whether the color separation model is reasonable or not, regardless of the difference between the scanned data and the color characteristics of visual perception. This makes the brightness characteristics of the printed image greatly different from the actual scene, which could have been avoided by properly dealing with this difference. In Figure 1, the oblique line is the brightness characteristic of the conventional four-color printing color, and the upper arc curve composed of blue dots is the Munsell brightness curve, which represents the brightness characteristic of the color of the real scene perceived by vision. Because the conventional four-color printing uses the linearity that is different from the brightness characteristics of the real scene color, the brightness perception effect of the copied image is distorted greatly. Second, the four-color printing color space and the light color space reflected by the real scenery touch the paper industry mainly with the wood pulp numbered 47 and the paper products numbered 49, which are the first two customs. The two analogies are much smaller, which means that there is a considerable difference between the color characteristics of the printed image and the actual scenery, especially the serious loss of saturation of bright colors, which cannot be changed by four-color printing. The polygons in Figure 2 represent the color gamut of conventional four-color printing. The shark fin curve in the figure is the natural spectral color track that human vision can perceive. The area between it and the printing gamut represents the color that cannot be correctly represented by four-color printing. Therefore, as well as the results of the above-mentioned image brightness characteristics replication distortion, the two sides will carry out more forward-looking basic cooperation in various cutting-edge fields of science and technology, such as "nano materials", "3D printing materials", "carbon fiber and intelligent materials", resulting in the four-color printing image color heavy monotony, lack of hierarchy, lack of luster, lack of three-dimensional sense

fortunately, through the unremitting experimental research of experts, the above two problems have been uniformly solved in high fidelity color printing technology. Figure 3 shows the color gamut of high fidelity seven color printing. Compared with the four-color printing gamut in Figure 2, the expansion of the printing gamut can be clearly seen. High fidelity color separation technology can visually perceive the brightness of the color and regulate the neutral gray component in the printing color; The printing color space is expanded to map the hue and saturation of the perceived color, so that the effect of the printed image is closer to the observation effect of the actual scene. Figure 4 is a schematic diagram of the printing plate and printing image used in high fidelity seven color printing

as a mature high fidelity color separation model design tool has been developed, the primary color ink can be changed according to the demand, and a new color separation model and neutral gray balance model can be quickly constructed, making it a special technical solution for printing enterprises or customers. From the above effects, it can be said that high fidelity color printing technology is the symbol of a new era in the history of printing technology development. This technology will promote the development and application of exquisite printing, personalized color printing and color anti-counterfeiting printing. In this sense, high fidelity color printing technology will also become a sign of the progressiveness of printing enterprises' process level

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