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The main idea of the structure of the printing process
control scale is that the
printing process is in many respects a probabilistic process, and the final result has a
certain degree of uncertainty.
The total transfer of paint is controlled by scale areas where the relative area of
the plate-raster points is 100%. The
plates can be square, rectangular, ribbon, circle,
etc.
The more paint control elements that need to be controlled,
the more control
elements will be available on the scale. The most common case is that the 4-color triad
print should have yellow, red, blue, and black plates on the scale. If additional dyes are
used in the printing, such as mixed (Pantone) or metallized dyes, the number of control
elements will increase accordingly. The optical density
of the plate in the copy is
measured with a densitometer, taking into account the whiteness of the paper (i.e., the
unprinted area of the paper is initially measured and this value is taken as 0.0 D (optical
density)). For triad printing on different paper varieties, there are standardized values
of the optical density of the plate for each dye.
The difference for zonal densities on colored inks when printing on corrugated
paper
according to the technical instructions for offset printing processes is
± 0.05 D,
in other cases
± 0.10 D. If the density values of the plates are lower than recommended
when printed, the image will be unsaturated and low contrast, if the density is high, the
dark areas will be copied with darkened and very saturated plates, the image will darken
and its contrast will decrease Value of scale optical densities for sheet-fed offset
printing (technical guidelines for offset printing processes developed by the Russian
Printing Research Institute)
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