What do you know about printing color sequence?
Time:2023-06-15
Views:802
First, the main reasons why the printing color sequence needs to be arranged:
There are three main reasons for the need to arrange the printing color sequence:
1. The influence of ink overprinting on each other and the shortcomings of ink color itself;
2. Quality of paper;
3. The human eye‘s ability to recognize color.
One of the most fundamental reasons is the incomplete transparency of the printing ink itself, that is, the hiding power of the ink itself, the post-printing ink has a certain hiding effect on the first printed ink layer, resulting in the color of the printed matter is always biased toward the performance of the latter color, or the mixed color of the former color and the former color.
Second, the factors affecting the printing color sequence:
1. Consider from ink transparency
The transparency of the ink is related to the hiding power of the pigment in the ink. The so-called ink covering power refers to the covering ability of the covering layer ink for the underlying ink. If the hiding power is poor, the ink transparency is strong, and if the hiding power is strong, the ink clarity is poor. Generally speaking, the ink with poor covering power, that is, strong transparency, should be printed at the back, so that the brilliance of the pre-printing ink will not be covered to facilitate the reproduction of color. Ink transparency relationship: Y>M>C>BK.
2. Consider from ink brightness
Low brightness first printing, high brightness after printing, that is, deep ink first printing, light ink after printing. Because the higher the brightness, the higher the reflectivity, the more vivid the color is reflected, and the overprint the light color on the dark color, the trace overprint is not allowed to be very conspicuous; If you put a dark color on a light color, it will show. In general, the brightness of the ink size relationship: Y>C>M>BK.
3. Consider the drying speed of the ink
Slow drying speed printing first, fast printing after. If the first printing is fast, for the monochrome machine, because it is wet pressed dry, it is easy to glass, which is not conducive to fixation; For multi-color machines, it is not only conducive to the overprinting of ink layers, but also easy to cause other ills, such as the back rub and so on. The order of ink drying speed: yellow is 2 times faster than red, red is 1 times faster than green, black is the slowest.
4. Consider the nature of the paper
1), surface strength of paper.
Paper surface strength refers to the binding force between the paper surface fiber and fiber, fiber and rubber, filler. The greater the binding force, the higher the surface strength, and the degree of depowder and hair removal on paper is often measured in printing. For the surface strength is good, that is, the binding force is large, not easy to powder, hair off the paper, we should first print the viscosity of the ink, the viscosity of the first color printing is also conducive to overprinting.
2), for the paper whiteness is good, should first print dark color after light color.
3) For rough and loose paper, print light color first and then print dark color.
5. Consider from the network area share
Print the small dot area first, and print the large dot area after. In this way, the printed image is richer and more vivid, and it is also conducive to the reproduction of the dot.
6. Consider the features of the manuscript itself
Generally speaking, the original can be divided into warm tone original and cold tone original. Warm tone of the original manuscript, should first print black and green, after printing magenta and yellow; The original manuscript based on cold tone should be printed magenta first, and then black and green. This will highlight the level of the main tone.
7. Consider mechanical properties
Because the model of the offset press is not the same, its overprinting method and effect are also different. We know that the monochrome machine is a "wet press dry" set, overprinting form, and the multi-color machine is a combination of "wet press wet" and "wet press dry" set, overprinting form, their sets, overprinting effects are not the same. Usually, the color sequence of the monochrome machine is: first printing yellow, and then printing magenta, blue and black respectively.
Three, the printing color order must follow the principle:
Printing color order will directly affect the quality of printed products, in order to obtain a good copy effect, must follow the following principles:
1. According to the brightness of the three primary colors, the color order: the brightness of the three primary colors of ink is reflected in the spectrophotometric curve of the three primary colors of ink, the higher the reflectivity, the higher the brightness of the ink. Therefore, the brightness of the three primary colors of ink is; Yellow > Green > Magenta > Black.
2. Arrange the color order according to the transparency and hiding power of the three primary colors of the ink: the transparency and hiding power of the ink depend on the difference between the refractive index of the pigment and the connecting material. The ink with strong covering has a greater impact on the color after the overlay, and it is not easy to show the correct color as the post-printing color overprint, and the good color mixing effect is not achieved. Therefore, the ink with poor transparency is printed first, and the post-printing with strong transparency.
3. Arrange the color order according to the size of the dot area: in general, the dot area is small and printed first, and the dot area is large.
4. Arrange the color order according to the characteristics of the manuscript: each manuscript has different characteristics, some belong to warm tone, some belong to cold tone. In the color sequence, the warm tone is mainly printed first black and green, and then red and yellow; The cold tone is mainly printed red first, and then green.
5. According to the different arrangement of the color order of the equipment: under normal circumstances, the printing color order of the monochrome or two-color machine is appropriate to alternate the light and dark colors; Four-color presses generally print dark colors first and light colors later.
6. According to the nature of the paper, arrange the color order: the smoothness, whiteness, tightness and surface strength of the paper are different, flat and tight paper first printing dark color, after printing bright color; Thick, loose paper, first print bright yellow ink, and then print dark color, because yellow ink can cover paper defects such as wool and powder.
7. Arrange the color order according to the drying performance of the ink: Practice has proved that the drying speed of yellow ink is nearly twice that of magenta ink, and the drying speed of magenta ink is twice that of green ink, and the fixation of black ink is the slowest. Slow drying ink should be printed first, dry fast ink after printing. In order to prevent glass transition, the monochrome machine generally prints yellow finally in order to quickly dry the conjunctiva.
8. According to the flat network and the field arrangement color order: when the replica has a flat network and the field, in order to obtain good printing quality, make the field plain clothing, the ink color is bright and thick, generally print the flat network graphics first, and then print the field structure.
9. According to the light and dark color order: in order to make the printed matter have a certain luster and add light colors, print dark colors first, and then print light colors.
10. Landscape products of the green layout text area is much larger than the magenta version, according to the principle of large graphic area of the color plate after printing, it is appropriate to use black, magenta, green, yellow order.
11. Products based on text and black field generally use green, magenta, yellow, black order, but can not print black text and patterns on the yellow field, otherwise due to the small viscosity of yellow ink, black viscosity and reverse overprinting, resulting in black printing can not be printed or printed false phenomenon.
12. For the four-color overprint area of the screen is very small, the color sequence can generally use the principle of a large graphic area of the color plate after printing.
13. Gold and silver products, due to the adhesion of gold ink and silver ink is very small, gold and silver ink should be placed in the last color as far as possible, and under normal circumstances, it is not appropriate to use three overlapping ink printing.
14. The color order of printing should be as consistent as possible with the color order of proofing, otherwise it will not catch up with the effect of proofing.
If it is a 4-color machine, printing 5 colors, it is necessary to consider the problem of embossing or overprinting, and the color overprinting of the general bite position is more accurate. If there is overprinting, be sure to do trap printing, or overprinting is not easy to leak white.
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Anna Zhang