Application of color management
At present, color management technology is mainly used in the three aspects of pre-press in the color printing and copying process:
1. Color separation technology
First of all, for a manuscript with normal color, first, scan and input it with a scanner. Due to the scanner’s characteristic file, the color on the scanner (ie, red, green, and blue) is provided corresponding to the CIEl976Lab chromaticity space. Therefore, the application software system can obtain the chromaticity Lab of the original color according to this relationship. Since the system has mastered the corresponding relationship between the Lab chromaticity value and the red, green, and blue drive signals on the display, the original color can be correctly displayed on the screen according to the conversion relationship given by the display’s characteristic file. This ensures that the color displayed on the monitor matches the color of the original.
After the operator observes the accurate image color display, he can adjust the image according to the screen color according to the customer’s requirements. In addition, since it contains the characteristic file of the printing equipment, after the image is separated, the correct color after printing can be observed on the monitor. . When the operator is satisfied with the color of the image, the image is separated and stored. During color separation, the correct dot percentage is obtained according to the color conversion relationship carried by the characteristic file of the printing device.
2. Screen soft proofing
The so-called screen soft proofing is a proofing method that simulates the printing output effect on the screen. This proofing technology is another proofing technology besides proofing on paper [Wikipedia].
The screen soft proofing completes the simulation of the image color on the monitor through special software, combined with device characteristic files, and through display device calibration.
Screen soft proofing technology requires the operator to skillfully apply color management technology to perform color matching, so as to realize the simulation of printing proofs.
3. Digital proofing
The working principle of digital proofing is different from that of traditional proofing. Digital proofing is based on a digital publishing and printing system. It uses the same page of graphic information to reproduce the effect of color graphics and texts by computers and related equipment.
The key of digital proofing is to output proofs that can simulate the effect of printing output to provide a basis for future printing work. The first step in digital proofing is to select or make a reference characteristic file corresponding to the characteristics of the printer. Put the printing reference characteristic file and the printing paper characteristic file into the corresponding area of
Implementation of color management
1. Standardized management of printing process
Elaborate the standardization and data management of each process, and establish the characteristic files of each process equipment on this basis, so that accurate color space conversion can be carried out.
According to the quality standards required by customers, formulate standards for substrates, inks, and other raw and auxiliary materials, as well as standards for equipment, environmental light sources, and testing, and develop standardized management documents.
Operate strictly in accordance with the work instructions, paying special attention to control points and control elements.
Quantification is carried out on the basis of standards and standardization. All aspects that can be represented by data must be tested and represented by data as much as possible. The three complement each other to achieve stable quality standards.
2. Display calibration
The monitor is a window between people and the computer and is a soft-proofing tool for prepress color management. It is one of the most important key links in color control. Calibration steps (using professional software).
Equipment testing-power-on preheating-connecting the measuring instrument-using the calibration software (setting the target, adjusting the contrast, brightness, Gamma value)-measuring the standard color patch-the calibration is completed.
3. Profile file management for remote digital proofing
If the plate making and printing are in two places, for example, plate making is in Shenzhen and printing is in Kunming, after the digital proofing is confirmed by the customer, the electronic file will be sent directly to Kunming, and then digital proofing will be carried out, and then printed accordingly. At this time, ensure the two places The digital proofing is consistent. To achieve this goal, you must:
(1) Inspect and control the printed standard test strips, and carry out standardized calibration once a week.
(2) The profile files established in the two places strive to be consistent so that the color and gradation performance characteristics are completely consistent.
4. Management of image technology
Image technology processing is the basis and key to copying.
①According to the printing suitability, make the built-in gray balance curve and color correction amount and calibrate with the standard black and white field to achieve the standardized restoration of scanning.
②Conscientiously implement the standards of gray balance, tone reproduction, color correction, and sharpness enhancement, and strive to achieve: The gray balance is restored accurately, and the best solid density value of the dot tone is fully utilized to achieve vivid color saturation. Sharpness is enhanced to make the image clear and fine texture.
③According to customer requirements, repair the defects of the original manuscript and perform the artistic treatment.
④In order to make the printed matter richer, the non-linear transmission of the printing process gradation is compensated.