The most popular packaging offset printing three

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How much do you know about packaging offset printing (III)

generally, when the point intersection angle is 30 degrees, the pattern is more appropriate. Because of poor color rendering, sometimes the intersection angle of yellow and light colors can be smaller

in the four-color printing process, there are four kinds of object point angles: 15 degrees, 45 degrees, 75 degrees and 90 degrees. In order to realize this feature, 45 degrees is used for adjustment and 90 degrees is used for yellow

in spot color printing, the monochrome layered printing or the monochrome layered printing overprint the field version, and the layered printing with a 45 degree angle is usually more beautiful; Two different colors of the layered version overprint, usually 45 degrees and 90 degrees; Three layers of different colors, usually 30 degrees, 60 degrees and 90 degrees

17. what effect does the dot shape have on the printing effect

The shapes of

points are round, square, rectangular and brick, which shall be determined during color separation and addition according to the contents of the original. Different shapes have different effects on printing reproduction. Round and square dots are used in daily production

the shape of the square dot is more regular than that of the next step. With the help of a small magnification, you can see the ink transfer in the printing process, which is convenient to control the printing quality. However, the square point has the longest at 50% and the point increase is the most serious, which is easy to cause the loss of the middle tone level

circular points also have the advantages of regular shape and easy to judge the transfer quality of points. The circular point has the longest perimeter at 755. The point expansion here is the most strict. Improving the energy utilization efficiency of the plastic granulator process and preventing and controlling environmental pollution are complementary. The dark high-level is easy to paste, while the point expansion below the middle and middle tone is small, and the level replication effect is good. Therefore, if the original picture is dominated by inter tone or high tone, circular dots should be used; If the image of the original focuses on the dark part, the square dot should be selected

in a word, the principle of selecting point shape is to minimize the loss of levels in the subject part of the original

18. what is the order harmonic level

the overall light and shade change of the image on the printed matter is represented by the overall tone of the image. The overall tone is described as a whole. The first level light and shade change from light to dark is represented as a level

19. what are the methods of expressing levels

the methods of expressing levels usually include continuous halo color tone such as photos and eye tone such as prints

20. what is continuous harmony

continuous tone means that the image of a picture is composed of extremely fine dye or pigment particles mixed in different proportions, and the color is in a continuous gradient state. Different composition, the continuous tone of the painting is composed of different density of various color particles per unit area

eye tone refers to the fact that the color change and depth change in printing are discontinuous in nature, and the color and tone change is expressed by the way of juxtaposing, overlapping or half merging and half overlapping of points of different sizes. Because the distance between points is smaller than the visual resolution of the human eye, the human eye will regard the eye tone image composed of color squints as a continuous hierarchical change and color change. However, if you observe it with a magnifying glass, you can only see a point with different size and color, and you can't see a continuous color and hierarchical change, such as negatives for plate printing, offset printing, etc

21. what is high profile, middle tone and dark tone

the bright part of the picture has a large amount of reflected light and a low density. If it is a visual tone, the part with a point size of 10% - 30% is usually called a high-profile part. The color part of the picture has less reflected light and higher density. In case of eye tone, the part with a point size of 70% - 90% is usually called the dark tone part. The part of the picture with the middle light and dark degree, the reflected light amount is between high and dark. If it is a eye tone, the part with a point size of 40% - 60% is usually called the middle tone

22. what are the three primary colors of color and light

according to the physical stimulation characteristics of light, human visual physiological characteristics and the results of a large number of color light mixing experiments, red light, green light and blue light can be mixed in different proportions to obtain all the remaining color light. However, table 2 test data of gold household socket materials show that none of the three can be mixed by any other color light. Therefore, red light, green light and blue light are determined as the three primary colors of color light. Since each kind of trichromatic light has a relatively large wavelength in the visible spectrum, each specific wavelength will have a corresponding different color perception for the stimulation of the human eye. In order to unify the understanding of trichromatic light, the international lighting Commission stipulates that the representative wavelengths of the standard trichromatic light are: red light 700mm, green light 546.1mm, and blue light 435.8mm. (to be continued)

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