Research progress of high fidelity printing techno

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The concept of high fidelity color printing has a long history. As early as the late 1990s, it began to enter the production workshop of printing enterprises from the laboratory, marking that the printing industry has entered a new era of color printing. Hi Fi color printing is relative to four-color printing. It improves the reproducibility and authenticity of printing colors by adding red, green, blue, orange and other color inks on the basis of C, m, y and K four-color printing. When printing with better ink, due to multi-color, the two colors in some four-color printing can be replaced by the primary color in high fidelity to make the color fuller. With the continuous improvement of people's pursuit of a better life, the requirements for the quality of printed matter are becoming higher and higher. At present, high fidelity printing technology has been more and more applied by printing enterprises. For color image printing, there is no other technology except high fidelity printing technology that can really expand the printing color gamut of the image, make the image color more bright and bright, more close to the viewing effect of the real scenery in nature, and achieve the highest printing quality level

II. The key technology to realize high fidelity printing

high fidelity color separation technology is the foundation of high fidelity printing and the key guarantee of printing quality. Since high fidelity printing uses more than four-color inks to copy the original, the conventional color separation method is not suitable. After the high fidelity printing process is adopted, the original will be multi-color separated. The specific color number is determined according to the specific situation of the original. The ink product characteristic values of different ink manufacturers are different, and the color separation systems established are also different. Color separation software can establish different color separation systems according to the needs of products and printing. At present, there are six color separation, seven color separation and even more color separation systems. This color separation technology is more complex than the four color separation technology. The high fidelity color separation technology is the core of the high fidelity printing technology. The high fidelity color separation is carried out in the ciergb color space. The input RGB color will obtain the brightness and chromaticity characteristics closer to the spectral color. Different primary color ink combinations match the input color chromaticity parameters of different hue ranges. The setting of the primary color ink color separation channel ensures that the printing color reaches the printing color gamut and realizes the gradient linearity. Compared with four-color printing, the color of high fidelity printing does not decrease in brightness due to the increase of saturation to some extent, which is impossible for 19000 retired employees of conventional four-color printing. At present, there are two kinds of known high fidelity color separation modes. One is the color separation model set in the interactive graphical interface represented by ICISS, and the other is the high fidelity color lookup table (cluts) fixed color separation model represented by Pantone hexarome

III. current situation of high fidelity printing

1 Research status

high fidelity color printing technology is the research content rising in the mid-1990s. Some internationally renowned companies, such as Heidelberg and Agfa in Germany, DuPont and Pantone in the United States, and aurelon in the Netherlands, have made useful explorations in this regard

① hypercolor high fidelity color separation scheme of hell and crosfield

high fidelity color technology of Linotype hell company adopts two scans to read color information: the first time to read CMYK information, the second time to read other three color information, and complete high-level gray component replacement at the same time of the first scan. The company adopts the VSF color system and has a certain expansion in the common directions of orange, emerald green and purple. In order to match the hypercolor scheme with the existing proofing and four-color printing processes, the company only uses CMYK as the basic color, generates seven color separations during color separation, and prints the same color again when CMYK reaches 100%. Hypercolor can adopt conventional addition technology, which can make the printed matter have 0 ~ 200% step change, and the maximum density can reach 2.2

② high fidelity color technology of saiangel

scitex's high fidelity scheme adopts CMYK four basic colors and their complementary colors, namely cmyk+rgb seven color printing. During scanning, only one scanning is completed for RGB. During processing, the input RGB file is decomposed into a CMYK file and an RGB file for printing. These two files can be used for image density correction and color adjustment in an interactive manner (not at the same time)

③ Barco's special multicolor separation software

the prepress system provided by Barco adopts the workstation of SGI movement and a series of professional software, including a software called ink switch, which can support high fidelity color printing technology and various special ink formulas. Users using Barco system first read the data of the ink of the color to be used into the workstation through the spectrodensitometer. During color separation, ink switch first converts the data into CIE color code, and then performs the second conversion according to the specified ink color system to generate the corresponding color separation chip. The software will give a warning when an unrepresentable color appears

④ Pantone hexachrome high fidelity color separation scheme

The basic idea of hexachrome printing is six primary colors printing. It uses the most basic CMYK four-color ink, and then adds green and orange for color reproduction. After adding these two colors, the printing color gamut is significantly expanded. In addition, hexachrome can accurately reproduce 90% of Pantone spot colors, while the traditional CMYK can only match 55% of Pantone spot colors. Hexachrome color separation is realized by a color separation software called hexware, which includes some plug-ins of Adobe software. It consists of two models, one of which is heximage, which is used for color correction and color separation. It can divide the color image into six separate gray-scale images. At present, the research on high fidelity printing in China is still in its infancy. Some research units have conducted research and experiments on it, but no mature scheme has been formed. The high fidelity color separation technology was first introduced by the Computer Research Institute of Peking University in 1994 with a color separation software that can realize seven color separation, which laid the foundation for the high fidelity color separation technology. Later, the founder Institute of technology of Peking University also introduced the high fidelity seven color printing technology. In 2002, the solor2.1 high fidelity color printing complete technology system based on the research results of high definition and high fidelity color printing complete technology under the technology innovation fund project of the Ministry of science and technology of the people's Republic of China was successfully developed. The technology research and development unit conducted on-site technical training and production guidance for the enterprise in the form of turnkey project until the actual production of qualified products

2. Application status of high fidelity printing in foreign countries, high fidelity printing has been applied in commercial printing, and as a development direction of sheet fed offset printing, its market prospect is promising. For example, hexchrome high fidelity printing is a multi-color double-sided printing process, which has the advantages of single channel, multi-color printing, high profit and high production efficiency. Japanese printing technology is famous for its high-quality and fine prints. In the field of multi-color printing, printing equipment with 8 or more colors has entered the Japanese market. Most of the formats are split, and some are as high as 10 or 12 colors. At the same time, 8-color A2 format and 6-color A3 format printing machines have also landed on the market. In addition, the 5-color double-sided printing machine has also appeared in commercial printing, but from the perspective of cost saving, the product research and development will focus on the web printing machine

in China, although high fidelity printing has made some phased achievements, for a long time, people's understanding of it has only remained on the surface, coupled with the limitations of software, equipment, personnel, etc., making its development relatively slow for a period of time. At present, high fidelity printing is still in the research and experimental stage in China, and has not been widely used in commercial printing, but this does not mean that there is no market for high fidelity printing. Many people think that high fidelity printing is not commercially viable. A common view is that modern printing can use some efficient solutions to print very good color images compared with the past. Choosing multi-color printing means to improve the workflow, and the increase in the number of printing colors will lead to an increase in printing time. The use of some current technologies, such as random dot and waterless offset printing, can already meet the current printing

3. Restrictive factors of high fidelity printing

the use of high fidelity printing will increase the production cost and have high technical requirements for the production process. For example, to use more plates and inks, the cost of four-color printing is much higher than that of four-color printing, and the amount of polyurethane in the automotive interior is much higher. In addition, there are also some factors that limit the substitution of high fidelity printing for traditional four-color printing, such as the wide use of multi-color printing machines, the cost of adding films, plates, proofs and inks, etc. In addition, the problem of creating effective color separation and combined high fidelity pages is also an important factor limiting the popularity of technology. The use of high fidelity technology requires the addition of color separation software. High fidelity technology also increases the requirements for the performance of the printing machine, which generally requires more printing units or multiple on-line printing

① insufficient demand

insufficient market demand is one of the most important reasons why hi fi cannot be popularized and popularized. The market competition in the printing industry is gradually moving towards standardization and normalization, and the market competition is relatively relaxed, which makes it not so urgent for printing houses and customers to adopt new technologies and personalized printing to improve their competitiveness. The lack of market demand is the reason why many printing manufacturers have not considered introducing high fidelity printing at all

② high cost

the price of supporting facilities required by high fidelity printing itself remains high. More color plates and inks are required for multi-color printing. In addition, there are costs of adding film, plate materials and proofing. The domestic PS plate can not produce the fine points required for high fidelity printing. Even if it is successfully printed, it cannot be successfully transferred to the printed matter. The technical development of domestic equipment and raw materials has not kept up, and the direct consequence is that most of the high-end plates and inks used for high-fidelity printing rely on imports, which greatly increases the cost, which also restricts the promotion of high-fidelity

③ process lag

high fidelity technology increases the requirements for the performance of printing machines, which can only be realized by using 6-color printing machines, which are expensive and complicated to operate. Secondly, the problem of creating effective color separation and combining high fidelity pages is also one of the factors that limit the popularity of these technologies. The use of high fidelity technology requires the addition of color separation software. In contrast, the current page combination and proofing methods are easier and cheaper. Thirdly, the plates used in high fidelity printing require that the photosensitive particles must be very fine. Finally, high fidelity technology has high requirements for originals. Nowadays, high-quality originals are rarely seen in China. They are usually ordinary photos, so it is difficult to ensure the completion of high-quality printing. These technical reasons limit the promotion of high fidelity to a certain extent

④ lack of talents

In 2000, the Ministry of science and technology of the people's Republic of China began to research high fidelity color technology, and in 2002, China had its own research results. It can be seen that the time for hi fi to enter China is still too short. Although the technical difficulties have been overcome, the talent reserve is seriously insufficient. The whole process of high fidelity printing from product design, plate making and printing to post press processing is very strict儿童消化不良怎么调理

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