How to restore the color and level of the color picture
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In the printing process of the color newspaper, there are many factors affecting the quality of the color newspaper, mainly the color and level of the picture, the ink color, the layout, the registration, the ink and water balance and the condition of the equipment. In actual production, we mainly control from the following five aspects.
The color and level of the picture are mainly related to the two processes of scanning and printing. When scanning, the originals are first classified (divided into fax pictures, photos, and secondary originals). The fax picture and the original picture are scanned with the appropriate number of lines after the aligned scanner lens. When processing the scanned picture, pay attention to 4 points: 1 to ensure that the highlight of the picture is not over the net; 2 to ensure the darkness of the picture The partial level is not leveled; 3 as far as possible to ensure that the middle adjustment level is rich, the brightness is moderate; 4 in the background color removal to ensure that the dark adjustment of the picture after the four colors overlap does not exceed 260% ~ 280%. For the secondary manuscript, in order to prevent the phenomenon of “mosquito” during the printing process, the scanner lens should be appropriately blurred before scanning or the image of the scanned second original is appropriately decontaminated after scanning. The scanning accuracy or angle rotation is less than 15°, and the focus is adjusted to a certain point. In these processes, the scanner's adjustment of the R, G, and B parameters of each picture is based on its own experience and the printing equipment conditions of the newspaper to judge its own processing effect.
For the production of the eyebrows, taking the Xinhua Daily as an example, the Xinhua Daily has a total of 16 editions of A, B, C and D. Each page has a standard color bar superimposed with four colors. The production of color bars consists of two aspects: 1100% of the dots mainly test hue and density; 230%, 50%, 70% of the dots mainly measure the increase rate of printing dots. We make this standard color strip for the following three functions.
1. In theory, the person who prints the ink color only needs to adjust the color of the day to the standard color strip, then the amount of ink in the photo above the color strip is basically in place.
2. When the exposure personnel adjust the exposure time and the developer concentration, the exposure time and the developer concentration can be determined according to the 3% to 4% of the dots in the highlight portion of the color strip.
3. The scanner can compare the difference between the effect of the picture above the color bar and the original according to the sample report when the color bar is adjusted to the standard color, and reflect on the R, G of the picture. Whether there is a need for further improvement in the B parameter, so that it can provide empirical data for scanning similar pictures in the future.