The influence of dot gain in printing plate drying

The commercial rotary press uses a soft and soft design where the blanket cylinders are each an impression cylinder. The paper completes the ink transfer under the blanket cylinder, and the dot expansion (mainly the mechanical dot expansion) is better than the sheet-fed offset printing press. Much larger, detected during multiple printing processes, considering different paper, taking into account mechanical and optical dot gain conditions, using the X-Rite528 spectrodensitometer to measure the start printing of the Heidelberg M-600 when normal, the printing outlets expanded Usually 13% to 19%. When printing the plates used in commercial rotary machines, increase the exposure and expose the small dots of 3% or less.

Mechanical dot gain is affected by many factors, such as ink, fountain solution, blanket, and paper surface properties. The main reason for the increase of the optical dot is that the refracted light increases the apparent area of ​​the dot. Because the dot area expansion will have a certain impact on the grayscale and balance of various colors of the printed matter, the version of the commercial commercial rotary machine can be lighter than the printing plate of the flatbed printing machine, and the exposure time is increased. The number of lines in the screen is In the case of 175 lines/inch, FOGRAl 982 test strips had a continuous density of 13 steps in the sun level 3, and a yin and yang micron concentric coil segment 811m in the yin and yang lines. If it is not 175 lines/inch, it is necessary to make reasonable adjustments according to the actual conditions of each printing factory.

Reprinted from: Print Channel