The desktop publishing system is an open system. Each device can only reproduce or display a specific range of colors. Scanners, monitors, and digital cameras generally use RGB space to express colors; and color printers, proofers, and photo images. Machines generally use CMYK space to express colors.
Due to the differences in the color characteristics of different devices and the influence of the use environment and device status, even the same device, its color characteristics are relatively unstable. The result of color reproduction depends on the device that produced it. Without understanding the differences between each device, the transfer of color information is bound to be greatly affected, and the desired color cannot be obtained.
The system characterization process of the device is essentially the formation of the color profile of different devices in the desktop publishing system, and the process of using the file to coordinate the entire desktop publishing system. In order to ensure the stability, reliability and continuity of the color information in the transmission process, the input, display and output devices must be systematically characterized to make the device in a standard state.
Color management is to detect a device through a series of color measurement tools, and draw the device's chroma or color gamut characteristic curve, and then make a device's color description file against a device-independent color model. And these color description files are the mutual conversion credential between the color space of the respective device and the standard and device-independent color space, which ensures the stability of the color characteristics of the device itself. ICC developed a cross-platform and system ICC standard to enable the sharing of color information in multi-device environments. In this standard, they define the format and type of the device's color profile and define a virtual device-independent color space. Then according to this format, the original device color space is converted to a virtual space, and then the virtual space is converted to the target device color space, thereby ensuring the correct transfer of color information in the input and output devices.
Color space conversion is the use of device-independent color space as a bridge for color image data and conversion between different devices. The conversion of color space involves two issues. One is the choice of color mode. The description of color in the color management process should be independent of the device. The Lab color space model defined in CIE is based on a large number of color vision measurements. It is independent of the device and is therefore widely used in color management systems.
The second is the mapping relationship of color space conversion. Due to the inconsistency of many color spaces, it will inevitably involve the problem of gamut compression or rejection. The colors displayed on the display screen and the colors output from the color printers, imagesetters, etc., as close as possible to the originals are the requirements and goals of the color conversion. However, since the CMYK space of the output device is narrower than the RGB space of the input and display devices such as scanners and displays, in the color space conversion, it is necessary to establish the compression and/or blanking of the color gamut that the scanner cannot cover for the ink. The relationship can ensure that the ink is as large as possible to reproduce the space in the color gamut. According to the requirements of color production and restoration, color conversion often uses the following methods. Each method is applicable to different objects.
1. Visual perception conversion. In the image copying process, the relative relationship of the original colors is maintained, that is, the conversion ratio is adjusted according to the gamut space of the output device, so as to obtain a mixture of colors in visual perception. This conversion is often used to restore higher-demanding continuous-tone originals.
2. Chroma conversion. Chroma conversion can be further divided into relative chroma conversion and absolute color conversion. The difference between the two lies in the difference in the color processing of the part of the matching color space before matching. The former replaces this part of the extra color with the border color, and the latter compresses this part of the color into the matching color space. This conversion is often used to adjust the display to ensure that the same color is obtained on different displays.
3. The best color gamut conversion. This conversion is required to produce the purest and most saturated color in the color space limited by the output device, instead of seeking to obtain the same color as the original or the display, and not aiming at the color matching between different output devices. This conversion method is often used for commercial printing with greater creativity.
In summary, to ensure maximum compatibility between desktop publishing system devices, it is necessary to implement effective color management. First, the color space of the entire system must be unified, and the unity of space must be independent of the device and color. A very wide range of Lab space or other suitable color space; secondly, the system equipment must be characterized, and the system's color profile file enables the system to be coordinated and unified when transferring color information; in addition, the color space conversion should be selected Independent of the device's color description language, and based on the color gamut expressed by the printing and printing, a suitable mapping relationship can be established. At the same time, we should choose the appropriate color space conversion method according to different situations.
In general, the specific implementation of color management can be divided into two types: one is the manual management method; the other is the software management method. The so-called manual management method refers to the measurement and adjustment performed for the color control in the input and output loops, basically relying on the judgement and alertness of professionals to implement the color management methods with calibration and calibration as the main means. The so-called software management method is a color management method using a color management system in a production system. The purpose of this method is to use the device and the originals, CMS can make the color from the display to the proofs to print the same effect. The user simply presses the button and the rest is done by the computer. For example, some color management software can convert scanners, color monitors, and final proofs or printed colors, and manage them in a coordinated manner, finally achieving WYSIWYG. As long as the user operates in accordance with the requirements of the color management software, the color management software automatically performs color compensation to finally achieve the best color reproduction effect. Even with no color processing experience or expertise, it is possible to produce satisfactory color pictures. In the entire process of printing and graphic reproduction, prepress processing is the key to the entire process. Giving full play to the maximum compatibility of the performance of each device before printing and implementing the most effective color management is the most important factor in achieving excellent quality of printed products. Of the ring.
(HC Network)
The united color as the kitchen cleaning supplies, is useful for cleaning kitchen items. Use the Scouring Pad with cleaning fluid can remove stubborn stains, used to clean and wash the dishes. It absolutely not damage the surface, durable, is the new generation of clean appliance. As kitchen cleaning supplies, It is very useful and have great effect. In addition to remove the stubborn stains, but also not damage the skin and kind to your hands.
Golden Silver Cleaning Sponge,Silver Cleaning Sponge,Kitchen Sponge Cleaner,Golden Sponge
FengRun Commodity Co.,Ltd. , http://www.yuan-qiang.com