In the printing process of color newspapers, there are many factors that affect the quality of color newspapers, mainly including the restoration of colors and levels of pictures, ink, layout, registration, ink and ink balance, and the status of equipment. In actual production, we mainly control from the following five aspects.
The restoration of color and gradation of a picture is mainly related to two processes of scanning and printing. When scanning, the originals are sorted first (separated into fax pictures, photos, and quadratic originals). Use the appropriate number of lines for scanning the fax image and the original photo after the aligned scanner lens. Pay attention to 4 points when processing the scanned image:
1, to ensure that the highlight part of the picture does not stop the network;
2, to ensure that the dark part of the picture does not level;
3, as much as possible to ensure that the middle tone is rich in levels, moderate brightness;
4, in the background color removal to ensure that the dark tone of the picture after the four-color overlay does not exceed 260% to 280%. For the second manuscript, in order to prevent "moiré" phenomenon from occurring during the printing process, the scanner lens must be properly blurred before scanning or the image of the scanned second manuscript should be properly decontaminated after scanning. Scanning accuracy or angle rotation is less than 15°, focus on a point to adjust virtual. In these processes, the scanning personnel's adjustment of the R, G, and B parameters of each picture is based on their own experience and the conditions of the printing equipment of the newspaper to judge their own processing results.
The production of Bao Mei, taking the Xinhua Daily as an example, Xinhua Daily has A, B, C, and D total of 16 color newspapers every day. Below each layout there is a standard color bar that is superimposed by four colors. The production of color bars involves two aspects:
1, 100% outlets mainly test hue and density;
2, 30%, 50%, 70% outlets mainly measure the printing dot gain rate. We make this standard color bar with the following 3 functions.
1 In theory, when a person who prints a color ink adjusts the day's color bar to be close to a standard color bar, the amount of ink in each color on the picture above the color bar is basically in place.
2 When the printing personnel adjusts the exposure time and the developer concentration, the exposure time and the developer concentration can be determined according to the dot condition of 3% to 4% of the highlights in the color bar.
3 The scanner can compare the difference between the effect of the picture above the color bar and the manuscript based on the sample report when the printing person adjusts the color bar near the standard color, and reflect on the R, G, and Whether there is room for further improvement in B-parameters can provide empirical data for scanning similar images in the future.