How Photoshop Controls Printing Color of Newspapers

With the rapid development of digital technology in the printing field, traditional printing methods have begun to be eliminated. In the process of digital printing, image processing software Photoshop plays a decisive role in image separation, and it is very important for the color control of newspapers before printing. Meaning, the level of Photoshop software directly affects the effect of newspapers, so it is necessary to have a deeper understanding and mastery of Photoshop. Here are just a few aspects to explain.

First, the color adjustment of the image processing host display to achieve WYSIWYG is the highest realm in the field of printing, but in actual work, due to differences in the hardware itself, changes in the hardware settings, and the instability of the printing process, so that people It is difficult to achieve the screen display effect that is the effect after printing. We want to make the screen display as close to the final print as possible, and minimize the visual error between the two. Specifically, under the condition of relatively stable printing, we use printed newspapers to adjust the screen display. Use Photoshop to open a layout image file and compare newspapers for correction. Go to the control panel and open the Adobe Gamma calibration program. Follow the prompts to complete the operation step by step. When adjusting the color, it is necessary to completely understand the additive principle of colored light, the principle of subtractive color of the color material, and the principle of complementarity of color, so that it is possible to accurately correct the effects of screen display and printed matter.

Second, adjust the scanner We all think that Photoshop software image file can be adjusted to a large extent, so ignore the scanner's correction, if the scanner is not adjusted to the best state, not only the image may be color cast, and the loss of image hierarchy, impossible Adjusted in the adjustment of Photoshop, generally many scanners have school color film, use it with random software adjustments.

Third, set color separation parameters Color image scanning is generally RGB mode, and then convert RGB mode into CMYK mode, this conversion process is completely based on our color separation parameters, different color separation parameter settings, the impact on the print Larger.
(1) The setting of outlet expansion rate: The expansion of outlets is entirely dependent on the characteristics of the ink we use and the printing characteristics of newsprint. The high-speed printing of rotation requires that the ink particle size cannot be too large and the liquidity is better, otherwise it will lead to the expansion of outlets. With the increase in the rate, the newsprint we use today is not coated paper. The domestic ink standards are not completely consistent with those of Europe and the United States. The ink color is not previously added to the ink table. In the table, we can find similar ink colors, domestic ink characteristics and The Toyo Inks standard is closer because it is more suitable for the Asian climate, so we chose the ink as the Toyo Inks (uncoated) standard with a dot gain rate of around 20%.
(2) Select the color separation type GCR and UCR, GCR is a gray component substitution (also called achromatic structure process), UCR is the background color removal. When printing on newsprint, the quality of the black version plays a decisive role in the entire printing process, generally adopting the default GCR.
(3) Set the tone of the black version: There are several black scale tone curves with less, medium, greater, and maximum ratios for selection. The general choice is less or medium, and the color level curve is more abundant.
(4) Set the maximum black ink volume. Different types of originals have different settings. The basis for this numerical setting is to ensure that the black print of the print is sufficient, with sufficient contrast, and conducive to the reproduction of the layers. The black version is generally limited to between 80% and 100%.
(5) Set the total ink volume: Due to the characteristics of newsprint and the high speed of offset printing, the total ink volume cannot be too high. Otherwise, the printed product will look like dirty. The total amount of printing ink is generally controlled. 260%-300% (the sum of CMYK four-color dots), this value is set by each process, and is entirely dependent on the dot gain rate during printing. If the dots are enlarged during printing, the value must be reduced ( However, it must not be less than 240%), otherwise the dark tone will be crushed, and the level of dark tone in the middle will be seriously damaged. If the dot enlargement is basically normal, you can increase the value properly (but not more than 280%) to ensure that the dark tone is black enough to fully represent the middle tone tone level, which is conducive to the reproduction of the entire tone. However, this value cannot be unlimited. Increase, otherwise it is not conducive to the improvement of printing speed, there will be many problems.

Fourth, adjust the color scale and saturation. Since our image is printed on newsprint, newsprint is colored paper with yellow in the black, so we must adjust the value of the intermediate scale from 1 in the adjustment of the color scale. To 1.6 or so, this will not be printed black print newspaper. At the same time, the saturation and brightness of the image should be adjusted so that the image is rich and bright.

Fifth, the resolution of the image processing There are many kinds of printing manuscripts, and the final effect of each different manuscript is different. Therefore, when processing in Photoshop, you need to deal with different requirements. In one case, for human figures, when doing sharpness processing, the skin must look fine and smooth, and the granularity of the skin should not be too strong; in order to make the figure three-dimensional, sharp outlines and important parts need to be sharpened. In addition, the USM sharpening of the blackboard of the image is performed for all the images. When the sharpening is performed, the numerical value may be given a larger value until the desired sharpness is achieved, but it may not be rough; it may also be separately applied to the image original. Different color versions handle sharpness and graininess so that better results can be achieved.

In general, the use of Photoshop software requires continuous improvement of the understanding of color and the use of various functions. It is necessary to be good at summing up, analyzing, and improving the quality of individuals so that they can control their color and print quality of color newspapers. Great improvement.

Article Source: Gold Online