Analysis of the most popular color image reproduct

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With the multimedia of image display and recording, the image information exchange between various media becomes more and more important. The reproduction quality of a color image in a medium depends on various technologies of the color reproduction system. These technologies include all aspects related to image reproduction. The author mainly analyzes them from the following aspects

1. selection of image data format

for a long time, the evaluation of image quality is determined by visual and subjective influence, which inevitably leads to the instability of judgment. Therefore, in order to have a standard basis, using a standard image data format will reduce the instability of image judgment. At present, it is generally recommended to adopt is012640 standard color image data format, which is the image data format adopted by color desktop system, high-end connection system, various output devices and digital printing system, and is independent of the device

for the widely used computer plate making system, standard color image data (using is012640 standard color image data format) is a very useful standard language. It provides users with image data that is independent of the original, input and output devices, and for various image processing systems and input devices. The post-processing process and the color copies produced by it not only provide observable, comparable and detectable means, but also provide operable general data standards

in this way, image reproduction between different media can make more accurate judgments, reduce the undue errors caused by subjective judgments, and improve the quality of image reproduction in the process of image reproduction

2. The theoretical basis of color reproduction

from other media to print media, is the main aspect of color image reproduction. The essence of color image printing is color dot printing, which reflects the light and dark level of color image by the size of dot area ratio, that is, the hue of the picture is reflected by the ratio of dot area ratio of C, m, y and K color plates

There are generally two common methods of dot color reproduction: one is Neugebauer equation based on halftone microstructure, and the other is mask equation without considering the specific structure of eye tone prints. But the premise of these two methods is to assume that the superposition law and proportional law of optical density are true. In practice, the correction of Neugebauer equation is often used to describe the reproduction of color

it should also be noted that the moire fringes often appear in dot printing have a great impact on the quality of image reproduction. Therefore, in order to reduce the impact on color image reproduction caused by this, a specific angle is often used in printing, that is, 45 ° for C version, 15 ° for M version, 0 ° for y version, and 75 ° for K version. At the same time, the number of dots and lines should also reach 70 ~ 80 lines/cm, so that the images that appear in the most widely used conventional plastic granulator equipment can meet the requirements

3. Play the role of black version in the process of image reproduction

in the process of color image reproduction, whether the black version is used properly will directly affect the quality of the reproduced image. In the process of color reproduction, the prominent role of black version is shown in: (1) strengthening the density contrast of images. These materials are being paid attention to in the vast user market to expand the brightness range. In this way, the total density range of the image is increased, the stereoscopic sense and spatial effect of the image are improved, and the image reproduction quality can be effectively guaranteed. (2) The black version can stabilize the color from the middle to the dark tone. For the reproduction of color images, the skeleton black version is usually used to enhance the outline of the image, and the specific use can be determined according to the characteristics of the image to be reproduced. Using appropriate black plates for superposition can also overcome the problem of dark and warm tones, and improve the satisfaction of the reproduced image effect. (3) Black version can increase the level of middle tone to dark tone. Due to the strong resolution of vision to dark tones, if the level from the middle to dark tones cannot be opened in the reproduced image, there will be a level merging phenomenon, and the use of black version can solve this problem to a certain extent

4. Deeply understand the importance of image hierarchy

image hierarchy refers to the density level from the brightest to the darkest on the image. Image hierarchy is a problem involving the whole process of color reproduction, and its importance can be seen from this

from the original to the printed matter, it needs to go through the process of color decomposition, splicing, copying, printing, and then to color synthesis. The whole process involves the hierarchy of the original. If the hierarchy deviation of a link exceeds the specified range, it will affect the subsequent process of obtaining the required data information, and the final hierarchy of the image must be difficult to maintain. Obviously, in the operation of the whole process, advanced equipment, raw and auxiliary materials with excellent performance, scientific processes and technologies. Close cooperation between plate making and printing is an indispensable prerequisite

generally speaking, the more the number of stages that can be distinguished in the reproduced image in the print, the more ideal the peripheral image level in the print, and the better the reproduction effect of the image

in a word, the color, tone, level and definition of the image constitute its final reproduction appearance characteristics. Whether the reproduced image can achieve tone coordination, clear level, reality but not lightness is the goal of color image reproduction quality

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