Standardization and dataization of color printing operation

2) Specification of photo management system management

Photocopying system management refers to ensuring the consistency of manuscripts, computer screens, proofing and proofing. Photographic system management includes the following:

1 scanner input calibration

The purpose of the calibration is to make the image data input by the scanner to the computer basically represent the characteristics of the color document. That is, whether it is a translucent document or a reflection document, the basic characteristics such as the reference white field, the neutral gray balance, and the level curve can be normal after scanning. Reflected in the image data. Therefore, the scanner should be calibrated frequently. It is necessary to continuously modify the relevant parameters in the scanning software. It is required that the output proofing be basically consistent with the original document without using computer image processing software.

2 computer screen calibration

Since the color gamut displayed on the screen has a large difference with the color gamut of the printing ink, if the screen display is not calibrated, and the operator lacks judgment experience on the color separation data, the effect after the computer processing will be completely reversed. Screen calibration method: Use the standard image data that has nothing to do with the scan input to output the color separation sheet, obtain the proofs under the premise of stable printing and proofing process conditions, and then use the screen calibration software to compare the proofs, after the color balance, brightness, and Gamma Adjustment of the curve, etc., makes the screen display almost the effect of proofs. It is best to self-proof or print the required chromatograms in a stable process.

3 Imagesetter output calibration

Fix the imager's laser intensity and adjust the film linearization under fixed conditions of the film and development conditions (time, temperature, developer's automatic replenishment, etc.). Compared with imported films, domestic films are less dense, have less contrast, and have poor linearity, which is detrimental to color reproduction. Therefore, when using domestic films, attention must be paid to the adjustment of linearization. In addition, the laser intensity is calibrated to ensure that the density on the dichroic plate is more than 3.5D. In general, the maximum density of the film is 3.5D or more and the gradation is lower than 0.07D in color newspaper printing.

3) Standardization of phototype operation

1 Image Scanning and Processing

Analyze the manuscripts correctly and classify them to facilitate separate scanning and processing, and determine reasonable scanning parameters based on the features of the manuscript. Generally pay attention to the following issues:

扫描 Scanners and originals should be kept clean;

要 When scanning, place the original in the middle of the scanning area as much as possible (because the color shift and sensitivity of the middle part of the scanner are better);

 For some important or poor quality manuscripts, the scanning resolution can be appropriately increased;

 In the case of guaranteed registration, sharpening may be appropriate;

色 For color shift, it can be adjusted through the color separation channel to give priority to the correct color of key parts;

阶 The tone levels should meet the needs of printing and should be concentrated in the middle area (20% to 60%);

彩 The headline character of the newspaper is generally a single color. Up to two colors can be used. Keep in mind the color of the stack. Only in this way can it be noticeable and conducive to overprinting.

 Add 80 to 100 lines;

网 Network point of view: characters Y90°, M45°, C75°, K15°; supplies Y90°, M45°～, C75°, K15°; black-and-white photos K45°; red photos 15°.
In the output process of the group edition, the two editions and outputs involve the steps of the upper edition, imposition, color correction, and distribution, etc. The following points must be noted during the operation:

 Picture should not be pressed in the groupware to avoid picture distortion and affect film output time and picture quality;

上 The CMYK format must be used in the upper edition image, otherwise the speed of the film is slow, and the RIP separation effect is poor;

 Color correction should be strictly in accordance with the editing requirements (for example, with the color version of a color version of the ink zone, the color registration should be M+Y rather than just the school M);

 Check whether the pictures and color blocks are accurate and whether the fonts have changed;

便于 Easy to make imposition, it is best to add crosshairs in the version software (Wits own centerline function, the centerline can not be too large, and the size should be the same;

ç…§ When the imagesetter outputs the film, the same newspaper is best to use the same imagesetter and developer;
 Accurately set distribution parameters, number of hanging lines, screen angle, mark, picture path, and output resolution must meet the requirements, and the resolution of color report output should not be less than 1800dpi;

保证 Ensure that the film is linearly correct. Each specific film type, lot number, punching machine, and liquid type should correspond to a linearized curve.

软 Film cleaners should be kept clean and well-functioning;

输出 The output of the film should be carefully examined: the film is not scratched, no horseshoe printed; register mark, full version; four-color film register, four film repeat positioning accuracy ≤ 0.05mm; film density is sufficient (D ≥ 3.5, gray Dmin ≤ 0.07), and uniform; pictures, text should be clear and distinct. (to be continued)