Reasons for inconsistency between proofing and print quality

Reasons for inconsistency between proofing and print quality

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1 The mechanical structure is different. At present, most of the proofing machines are usually platform machines, mostly monochrome or double-colored. The printing method is round-flattening. The ink is transferred between the platen and the impression cylinder (the blanket cylinder is used as the impression cylinder), and the printing paper is also Flat, and printing usually use monochrome, two-color or four-color and other complex printing presses, pressurization is through the imprinting cylinder and the rubber cylinder round printing method, the printing plate is also wrapped in the roller on the paper in the printing It is also round.

2 Different printing speeds. There is a big difference in printing speed. The printer can print more than 5000-6000 papers per hour, while the proofing machine can only print about 200 sheets at the fastest. The rheological characteristics of the ink used (such as viscosity, fluidity, etc.) are also different, and the fountain solution is also supplied in different ways. This affects the creation of dots, ghosts, and other unstable factors, resulting in reproducibility of the tone. difference.

3 The two inks are overprinted in different ways. On the printing press, when the first color ink has not dried yet, the next color ink is printed on it, and the proofer is after the basic color ink has dried, and then the next color ink is overprinted.

4 The layout of the printing plate is inconsistent with the printing requirements. The current method of inking causes excessive or insufficient tone in the layout.

5 Proofing and formal printing are different from each other. Due to the relationship between the resistance to printing force and exposure during printing, the sun exposure of proofing and the printing effect of printed printing are naturally different.

6 Proofing is different from printing paper. Different paper quality, different ability to accept ink, its absorption and reflection of light is also different, the inevitable print quality is also different.