Four-color
printing is the most basic printing method in brochure printing, and its
requirements are very high. For professional Chinese printers or book printing companies, the
mastery of printing colors is a very important basic skill, so what are the
rules for color matching in printing?
One
primary color or two primary colors can be used to print pure colors. The
chroma depends on the number of primary color inks. The more the number, the
higher the chroma.
The
hue obtained by printing with two primary colors depends on the relative
proportion of the two primary colors, and the hue of the printed color is
biased toward the color with a large proportion.
Adding
a third primary color on the basis of the pure color of the two primary colors
makes the saturation of the printed color lower and the brightness
correspondingly reduced, while the hue of the printed color is basically
unchanged, because the mixing of the three primary colors will form achromatic
colors. The effect is similar to the effect of printing with fewer colors of
the same proportion and a certain amount of black ink, such as light and dark
color series and dark and dark color series and three-color printing colors.
Increasing
the amount of black ink on the basis of color will not change the hue of the
mixed color, and will reduce the color brightness while also reducing the chroma.
In color printing, this feature is often used to reduce the amount of color
ink, which is called background color removal (UCR) and gray component
replacement (GCR).
Generally
speaking, in the technology of four-color printing, the color of the picture is
the most important issue. Therefore, we must pay attention to the color problem
in four-color printing.
1.Hollow
out
There
is a line of blue characters pressed on the yellow bottom plate, so on the
yellow plate of the film, the position of the blue characters must be empty.
The opposite is true for the blue version. Otherwise, the blue thing is
directly printed on the yellow, the color will change, and the original blue
character will become green.
2.
Overprint
There
is a line of black characters pressed on a certain red plate, so on the red
plate of the film, the position of the black characters should not be hollowed
out. Because black can hold down any color, if the black content is hollowed
out, especially some small text, a slight error in printing will lead to white
edges, and the contrast between black and white is large and easy to see.
3.
Four-color black
This
is also a more common problem. Before outputting, you must check whether the
black text in the publication file, especially the small print, is only on the
blackboard, and should not appear on the other three-color plates. If it does,
the quality of the printed product will be discounted. When the RGB graphics
are converted to CMYK graphics, the black text will definitely become four-color
black. Unless otherwise specified, it must be processed before the film can be
output.
4.
The picture is in RGB mode
When
outputting pictures in RGB mode, the RIP system generally automatically
converts them to CMYK mode for output. However, its color quality will be
greatly reduced, and the printed product will have a light color, not bright,
and the effect will be very poor. The picture is best converted to CMYK mode in
photoshop. If it is a scanned manuscript, it must go through the process of color
correction before the picture can be used.
Feel free to contact us to learn more about four-color printing
knowledge, as a professional Chinese
printer, we will do our best to serve you.