Determination of color sequence of lithographic offset printing

I. Determine the printing color sequence according to the nature of the ink

1) The transparency and hiding power of the ink depends on the difference between the refractive index of the pigment and the binder. After the multi-colored ink with high transparency is overprinted, the color light of the ink layer below can pass through the ink layer above to achieve a better color mixing effect and obtain bright colors. The comparison sequence of ink transparency is generally as follows: yellow> magenta> cyan> black, so the ink with poor transparency is printed first, and the ink with high transparency is printed afterwards.

2) The viscosity of the ink takes into account the printing sequence. In a four-color ink, each type of ink has a different viscosity, and the general viscosity is compared as follows: ink>cyan>magenta>yellow, so the color printing sequence of black, cyan, magenta, and yellow is generally used in a four-color printing press, increasing The firmness of overprinting prevents the phenomenon of “darkness” and the hue of the ink is changed, resulting in blurred images, dull colors, and dullness. Two-color machine uses cyan, magenta and black, yellow printing color sequence, ink absorption, easy drying, anti-dirty.

Second, according to the printing of the original to determine the color printing sequence

According to the contents of the printed manuscript, the principle of highlighting the main color is adopted to prevent the main color from being covered. The main color version is printed at the end. For example, the portrait of a person, the leaves of a mountain, and the landscape of autumn scenery need to be enhanced and the warm tone is printed first. Green, yellow, after printing magenta, yellow; such as the spring landscape, landscape or snow-capped mountains of the picture, to strengthen the cold tone, the first black, magenta, blue and yellow.

Three. Layout ink size determines the printing color sequence

Whether it is a monochrome machine or a multicolor machine, multi-color printing is always printed in one color and then printed in a color version. If a large-area field version is arranged in the first color, then other light-ink printing plates are printed. The printing effect is certainly not ideal, easy to scratch, poor ink absorption, dot flowers, difficult to dry. According to the first printing of light ink, after printing a large amount of ink plate color order.

The color version of the two-color machine should also follow the principle of large- and small-ink printing, and the large-ink printing plate should be placed in the second color group to prevent “coloring”.

Four. According to the requirements of the overprint to determine the printing color sequence

1) Four-color overprint. The overprinting may be affected by factors such as the paper absorbing deformation or its own resistance to tension and the problems of plate making. If the black text of the layout is mistaken for four-color characters, the printing order of yellow, magenta, cyan, and black can be used for monochrome machine printing, which can add gray balance and enhance the outline of the picture; some manuscripts often appear overprinting of blue and magenta solid texts. Once the standard is not very beautiful, if the magenta and yellow overprint of the red text is not obvious because of overprint problems. In the two-color machine should be used cyan, magenta and black, yellow version of the printing color sequence, the effect is more ideal.

2) Printing gold and silver. Gold and silver inks have very low adsorption power and are printed on the last color possible; however, the hiding power of the two oils is extremely strong, and the ground version will cover all the colors. It is necessary to consider the issue of platemaking. Gold or silver printing blocks are used to print four-color printed text, or whether images are hollowed out. When they are not empty, they are printed with gold or silver plates. If you do not pay attention to such problems, you will lose the content.

3) Print black text on the field version. Often encountered in the printing, the first printing of black text after the print magenta, yellow or spot color version of the text is reddish or yellowing, should be selected before printing the ground color after printing the black version of the printing color sequence.

Five. The color of the paper should be considered different

The color printing paper is selected from different paper, the paper's whiteness, smoothness, ink absorption, fiber loose, off the powder lint is not the same; coated paper nature is more stable, other paper such as offset paper, writing paper, white paper , Textured paper and other rough surface, poor resistance to tension, in order to make up for the lack of paper surface, you can first print the yellow version of the primer.

VI. Printing sequence in visual effects

In the past, monochromatic printing often arranged yellow printing in the first color. Under light, yellow ink was visually weak and the amount of ink was not good. Strong ink can be selected to be printed in the first color, such as the printing color sequence of cyan, magenta, yellow, and black, which is more convenient for visual or ink replacement, and at the same time preventing the glass plate from rapidly drying due to an excessively long interval. Phenomenon.

In the production process, experience should be summed up for the printing color sequence for different printing equipment, paper, ink and different manuscripts. By referring to the proof sheets, checking the printing plate, and selecting the correct printing color sequence, a satisfactory overprinting effect will be finally obtained.



Reprinted from: Shaanxi Printing