The three main reasons leading to the need for color sequencing

The yellow, magenta, cyan, and black printing sequences used in traditional printing processes are because the yellow ink was the most opaque at the time and the hiding power was so strong that it was necessary to print the yellow ink first, otherwise it would produce a great deal of overprinting. influences. Now this kind of traditional color sequential arrangement method has gradually been eliminated, because the yellow ink produced is now better transparency, reducing its impact on the overlay color, but also allows printers to reconsider the traditional printing color sequence arrangement The field density is used as a means of controlling color, dot gain, and ink overprint on a four-color machine, and thus new cyan, magenta, yellow, and black (or black, cyan, magenta, and yellow sequences) have become the commonly used color sequence. .

There are three main reasons that cause the color sequence to be arranged: (1) the effect of overprinting of the ink and the disadvantage of the ink color material itself; (2) the quality of the paper; (3) the ability of the human eye to recognize the color. The most fundamental reason is the incomplete transparency of the printing ink itself, that is, the hiding power of the ink itself, and the ink after printing has a certain hiding effect on the ink layer printed first, resulting in the color of the printed matter always showing a heavy emphasis on performance. The colors, or rather, the mixture of the rear and front colors.

1. Consider the brightness of ink

The low brightness of the first printing, the high brightness of the post-printing, which is the dark ink of the first printing, the ink after the shallow printing. Because the higher the brightness, the higher the reflectivity, the more vivid the colors reflected, and the light color overprinting in dark colors, the appearance of misprints is not accurate and not conspicuous; if dark colors are set on light colors, they will be exposed. . In general, the relationship between the brightness of the ink: Y>C>M>BK.

2. Consider ink transparency

The transparency of the ink is related to the hiding power of the pigment in the ink. The so-called ink hiding power refers to the covering ability of the overlay ink to the underlying ink. If the hiding power is poor, the transparency of the ink is strong, and if the hiding power is strong, the transparency of the ink is poor. In general, inks with a poor hiding power, that is, a transparent ink, should be printed behind, so that the brilliance of the ink before printing will not be covered in order to reproduce the colors. The strength of ink transparency: Y>M>C>BK.

3. Consider the ink drying speed

Drying slow printing, fast printing. If the first printing is fast, for a monochrome machine, since it is wet and dry, it is easily vitrified and is not conducive to fixing; for a multicolor machine, it is not only unfavorable to the overprinting of the ink layer, but also causes other disadvantages, such as Dirty back and so on. The order of ink drying speed: yellow is 2 times faster than red, red is 1 times faster than green, and 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 fiber and fiber, fiber and rubber, and filler on the surface of the paper. The greater the binding force, the higher the surface strength, and the degree of de-dusting and lint-eating on the paper surface. For a good surface strength, that is, a combination of large, difficult to remove powder, lint-free paper, we should first print a large viscosity ink, the viscosity of the first color printing is also conducive to overprinting.

(2) For the whiteness of paper, it should be printed in dark color and printed light color.

(3) For rough and loose paper, first light color and then dark color.

5. Considering the market share of outlets

The first printing of the small area of ​​the network, the printing of the large area of ​​the outlet. The images printed in this way are richer in color and more vivid in levels, and are also advantageous for the reproduction of outlets.