How to restore the colors and levels of colorful newspaper pictures

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). Scan the fax image and the original photo with the appropriate number of lines behind the aligned scanner lens. Pay attention to 4 points when processing the scanned image: 1) Ensure that the highlight part of the image does not stop netting; 2) Guarantee the darkness of the image Adjust the level of some levels are not combined; 3 as much as possible to ensure that the tone of the middle tone is rich, 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 includes two aspects: 1100% outlets mainly test hue and density; 230%, 50% and 70% outlets mainly measure printing outlets. We make this standard color bar with the following 3 functions.

1. In theory, when a person who prints a color ink just adjusts the color bar of the day to be close to a standard color bar, the amount of each color of the picture on the color bar is basically in place.

2. When the plate-making personnel adjusts the exposure time and the developer density, the exposure time and the developer concentration can be determined according to the dot condition of 3% to 4% of the highlight portion of 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 of the picture that he is dealing with. Whether or not there are areas for further improvement in the B-parameters, this can provide empirical data for scanning similar images in the future.