Feel the most popular color management around 1

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Feel the color management around you (1)

not long ago, an advertiser asked: why is the same advertisement published in four different magazines with the same film printed with different effects. In fact, this involves the color management in the process of image printing and reproduction. Although many books and magazines have introduced the color management system, most of them focus on the principle introduction and theoretical discussion, and rarely involve the actual application and working process. In the process of communicating with some peers, the author feels that there are still some problems in our understanding of color management and in the specific application

in fact, color management is around us. Nowadays, the process of color image printing and reproduction, whether from image scanning, processing, printing, film production, plate printing, or CTP direct plate making, to printing, inevitably involves color management. Whether you like it or not, consciously or unconsciously, the color management system will inevitably affect the changes of color. The original intention of the color management system is to get the image color from the printer or printer on the computer screen, and truly realize WYSIWYG. In principle, color management is to convert the image color in the color space of different devices, so that the image color can still maintain visual consistency after being processed by different devices. The correct use of color management system can restore the image correctly in the process of printing and copying. However, if used improperly, the color management system itself will also become a factor affecting the correct restoration of image color

there is a view that the application of color management system completely abandons the traditional point replication theory. In fact, color management theory is based on point replication. Therefore, some people think that color management is the traditional way to solve the current problem since May this year. Although the application of color management system can realize the reproduction of color, it may not realize the idealization of image reproduction only based on color management. It is also necessary to use image processing methods and skills based on point structure and replication principle to copy and restore images correctly

1. From the perspective of Photoshop, the role of color management system

in theory, a color management system is just a color in one color space corresponding to a color in another color space. However, in specific applications, we can feel that the color management system is just some so-called device color characteristic files. How the color characteristic file of this device restricts and affects the change of color in the process of image reproduction needs special attention. Although the role of color management system runs through the whole process of color image reproduction, the key operations are mainly concentrated in the prepress stage. This paper will mainly discuss the role of color management system in image processing from the concrete and application of color management system in each process of Photoshop Image processing. 1. image mode conversion and color separation open Photoshop, click the color setting in the toolbar, where there are RGB, CMYK, gray, spot color and other options in the color space. They correspond to the color space of computer display, printing or proofing, monochrome (black and white) printing and spot color printing respectively. Among these options, selecting the color profile corresponding to these devices, that is, the so-called equipment and instrument archives, is an important basis for realizing the correct use and scientific management of equipment and instruments. For the actually measured color characteristic files of printing or printing equipment, they should be added to the corresponding color space by loading

multiple modes of color should be applied during image reproduction. Different modes of image color have different color spaces. Color space usually refers to the space model used to describe the color composition. Because there are many assumptions about the color composition methods, and each method has its unique characteristics and applications, a variety of image modes have been formed, such as RGB, CMYK, lab, etc

most digital images scanned from pictures or obtained directly from digital cameras adopt RGB mode, and computer display usually also adopts RGB mode. This is a color mode based on the principle of color light synthesis, but color printers and printers use CMYK color materials to form colors through the stacking or mixing of color materials, so RGB image mode cannot be directly applied

an image is usually processed through scanning, display, printing, color separation output or direct plate making before printing can be completed. However, different devices often adopt different image modes, which makes it difficult to transfer images between different devices. Therefore, in order to enable the image to pass unimpeded between various high-speed and high-frequency positioning function devices, we must first solve the problem of image mode conversion

there are many common and commonly used image modes. Even the most common RGB modes are actually several. RGB mode obtained directly from digital camera or scanner has the characteristics of complete information and wide color gamut. But at the same time, it also brings a large amount of information and data, resulting in the speed problem of computer processing, display and transmission. Compared with the conventional RGB mode, the CMYK gamut used in color printing and printing is much smaller. In the process of image processing, when the RGB mode image is converted to the CMYK color mode applicable for printing or printing, the color beyond the CMYK mode color gamut will be replaced or discarded. At the same time, because its color gamut range greatly exceeds the color range of printing or printing, in the process of converting RGB mode to CMYK mode, the images displayed by the computer often have obvious changes

Photoshop uses AdobeRGB1998 for image processing and display. Although AdobeRGB1998 belongs to RGB mode, its color gamut is much smaller than that of conventional RGB, and the image is closer to the printing and printing effect on the computer display. Therefore, it is usually selected as the image mode for computer display in the image processing process for printing and printing. The simplest way to adjust the computer display screen to AdobeRGB1998 mode can be completed with the help of the gamma~ tool provided by Photoshop. Generally, as long as the operation instructions are strictly followed and carefully adjusted for several times, the requirements can be basically met

as for the ARGB mode, it has been reported that it will become a common image mode for networking and printing. Although this image mode has the advantages of small amount of data, easy network transmission and computer processing, it also has the problem of easy loss of details. At least for now, it is difficult for the publishing and printing circles to accept

the image mode suitable for printing or printing is CMYK. Its color is composed of the percentage value of the dot area of C, m, y and K inks. The colors of R, G and B are composed according to the percentage of the density of the three primary colors, which is very different from the color space of CMYK. The process of converting RGB mode colors to CMYK mode is usually called color separation. The basis for decomposing R6b color and then synthesizing CMYK color is the color characteristic file of printing or printing equipment. Fig. the mode conversion and color separation of Jinan assay work notice image at the end of the holiday on October 1 are important tasks of image processing. In the process of mode conversion and color separation, the color characteristic file of the equipment plays a decisive role

open any picture in Photoshop and move the mouse over the picture at the same time. The R6b data and CMYK data of this color will be displayed in the information box in real time. Change the option of CMYK color space, such as changing from Japanese standard to American standard or European standard. The CMYK data displayed in the information box will change, but the RGB data will not. This shows that photoshop~ changes the CMYK data of the image according to the color characteristic file of the device. However, while changing the CMYK data, the RGB data does not change, which indicates that the color of the image remains unchanged when changing the chyk mode. In other words, when the printing or printing equipment changes, as long as the corresponding equipment characteristic file is selected, the image color remains basically unchanged. This is the role that people hope color management system can play in the process of image reproduction

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