How to determine the printing color sequence of th

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How to determine the printing color sequence of offset press

offset press is a kind of circular press. According to the principle of indirect printing, the printing plate transfers pictures and texts on the substrate through the rubber cloth transfer cylinder for printing. How to determine the printing color sequence of offset press? Please look at the sorted materials

I Determine the printing color sequence of the offset press according to the nature of the ink

1) the transparency and hiding power of the ink depend on the refractive index difference between the pigment and the binder. After multicolor overprint with high transparency ink, the color light of the lower ink layer can pass through the upper ink layer to achieve better color mixing effect and obtain bright colors. The contrast order of ink transparency is generally as follows: yellow, magenta, red, cyan and black, so the ink with poor transparency is printed first, and the ink with high transparency is printed later

2) the printing color sequence shall be considered for the viscosity of ink. Among the four-color inks, the viscosity of each kind of ink is different. The general viscosity comparison is as follows: ink green, magenta and yellow. Therefore, the printing color sequence of black, green, magenta and yellow is generally used in the four-color printing machine to increase the firmness of overprint and prevent color channeling. The ink hue is changed, resulting in blurred picture, gray color and lusterless. The two-color machine adopts the printing color sequence of cyan, magenta, black and yellow. The ink has strong adsorption, is easy to dry, and is dirt proof

II Determine the printing color sequence of the offset press according to the printing manuscript

according to the content of the printing manuscript, follow the principle of highlighting the main color of the screen to prevent the main color from being covered. Generally, the main color version is printed last. For example, for the pictures of the company's secretary office, red leaves in the mountains, and autumn landscape called by the figure painting "daily economy" on Sunday (November 26), it is necessary to strengthen the warm colors, printing black and green first, and then magenta and yellow; For example, the pictures of spring scenery, mountains and rivers or snow mountains should be printed in black and magenta before cyan and yellow

III The size of the layout determines the printing color sequence of the offset press

whether it is a monochrome machine or a multi-color machine, the multi-color printing always prints the next color version after printing one color. If the large-area field version is arranged to print in the first color, then print other light ink printing plates. The printing effect is definitely not ideal, easy to scratch, poor ink absorption, dotted, and difficult to dry. You can press the color sequence of printing plate with light ink volume first and then large ink volume

the color matching of the two-color machine should also follow the principle of printing with large and small ink volume. The printing plate with large ink volume should be placed in the second color group to prevent color shifting

IV Determine the printing color sequence of the offset press according to the requirements of overprint

1) four color overprint. Overprint is affected by factors such as the failure of the experimental machine to operate normally due to water absorption and deformation of the paper, its own tension resistance, and the problems existing in plate making. If the black words on the layout are mistakenly made into four-color words, the printing sequence of yellow, magenta, cyan and black can be adopted for monochrome machine printing, which can supplement the gray balance and strengthen the picture outline; Some manuscripts often appear green and magenta field text overprint. Once the overprint criteria are not beautiful, if the magenta and yellow overprint golden red text is not very obvious due to overprint problems. The combination of cyan, magenta, black and yellow printing color sequence should be used in the two-color machine, and the effect is ideal

2) printing gold and silver. The adsorption of gold ink and silver ink is very small, and they should be printed in the last color as much as possible; However, the hiding power of the two oils is very strong, and the field version will cover all the background colors. We must consider the problem of plate making, whether the text or image of the gold or silver plate is hollowed out. If it is not hollowed out, the gold or silver plate will be printed first. If we do not pay attention to such problems, the content text will be lost

3) black text is printed on the field version. It is often encountered in printing that the black text is printed first and then the magenta, yellow or spot color version is red or yellowish. The printing color sequence of printing the field background color first and then the black text version should be selected

v Different paper properties should be considered in the color sequence

the paper used for color printing is different, and the whiteness, smoothness, ink absorption, fiber looseness, de powdering and hair loss of the paper are different; The nature of coated paper is relatively stable. Other papers, such as offset paper, writing paper, whiteboard, cloth paper, etc., have rough surfaces and poor tension resistance. In order to make up for the lack of paper surface, yellow version can be printed first for backing

VI The printing color sequence of offset press in visual effect

in the past, monochrome machine printing often arranged the yellow version to be printed in the first color. Under light, the yellow ink was visually weak and the ink volume was difficult to master. Strong color ink can be selected for printing in the first color, such as cyan, magenta, yellow and black printing color sequence, which is more convenient for vision or changing ink color, and at the same time, it can prevent vitrification due to long interval and rapid drying of yellow plate

in the production process, for the printing color sequence, the black roof and silver gray frame should not only show a cool experience, but also aim at different printing equipment, paper, ink and different originals. By referring to the external understanding of foam, which is usually limited to soft foam and foam samples for furniture decoration, checking the printing plate, and selecting the correct printing color sequence, we will finally get a satisfactory overprint effect

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