The relationship between color removal and image tone reproduction quality

There are many factors that affect the image tone reproduction that can be reasonably used to remove the amount of background color, and there are differences in the sum of the coverage of the four editions of the dots in different periods. In the 1970s, China had more monochromatic machines and two-color machines, and fine-quality printing products were adjusted to 320% to 340% (yellow 80% to 85%, magenta 80% to 85%, and green 85% to 95%). Black 70% to 80%); General print is 280% to 320% (Huang 70% to 80%, Magenta 70% to 80%, Green 80% to 90%, Black 80% to 90%), Germany Haier The extension offers 240% (yellow 50%, magenta 50%, green 60%, and black 80%). The longest and shortest difference between this expression and the fourth-order tone is 120%.

The main reason is that the printability is different. If the same printability conditions are printed with 240% and 360% adjustment, the product quality is definitely different. It is necessary to integrate various conditions, and the advantages and disadvantages are reasonably used. . At present, the printing press is developing at a high speed and with multiple colors. The overall tone of the printing plate is developing toward relatively short and square degrees. High-speed multi-color machine printing newspapers (newspapers) The total network coverage is controlled at 240% to 260%. The basic color of the plate is used. The opposite color is used less, the order is called, the cable is relatively thick, and the background color is relatively large; Color rotary printing (offset paper or low-weight coated paper), the total dot area coverage is controlled at 260% to 280%, corresponding adjustments in plate making; multi-color sheetfed printing fine products (coated paper).

The coverage of the total network area is controlled between 280% and 320%. Under normal circumstances, as much as possible, bright or slight emphasis is maintained during pattern making, moderate compression or medium compression, dark compression, and the amount of background removal is relatively small. Medium to dark tone level. The overall tone value is longer, because of the black version of the compensation function has lost the necessity; the overall tone value is shorter, has done experiments, such as 220% (yellow 40%, magenta 40%, blue 50%, black 90% ), The results generally look gray, hue hard, middle tone thin. If the coverage of the total network area is shorter, the product quality requirements will not be met. Therefore, the reference that "the total coverage of four-color printing outlets is controlled between 200% and 300% is better" requires research or experimentation.

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