The setting of the most popular black version tone

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Black version gradient setting and printing quality (Part 1)

[Abstract] black version is not only used in gray and black parts of the image, but also used in all multicolor. Therefore, the setting of black version tone has a direct impact on the color effect, dark tone density and overall reproduction quality of printing

key words: Black Edition; Step; Background color removal

Chinese drawing classification No.: ts801; Ts805.3 document identification code: B Article No.: 1 but if the market order is not guaranteed (2003)

the setting up of the graduation of black and the quality of press product Liu Xiao Xia, Ding yi

(Shanxi University of science and technology, Xianyang 712081, China)

abrstract:the black plate is used not only in the gray adn black part of picture, but also in all the compound color erefore,the sutting up or the gradation of black plate will affect the color effect of press product, thd density fo shade tone and the quality of duplicating.

Key words:Black plate; Gradation; Under color removal

the color image shall be able to reproduce all the gradients of the original image after color decomposition and synthesis. However, due to the chromaticity characteristics of the actual ink and insufficient overprinting, and the influence of plate making on the compression of image gradients, the restoration of color and gradients of color prints is not ideal, especially the image torque is that the dark part density of the required torque is not enough, resulting in insufficient image contrast; Neutral grey of three color reproduction is also prone to color deviation in the direction of "functional, ecological and high-end" high technology. Therefore, in color printing reproduction, it is necessary to add a black plate to make up for the deficiency and deviation of printing, so as to improve the quality of printing

1 the role of black plate in color printing reproduction

a. increase the density and contrast of printed matter, increase the maximum density from about 1.7 to about 2.0, and improve the reproduction of image gradation and color; b. Stabilize and strengthen the color and level from the middle tone to the dark tone, and stabilize the reproduction of neutral gray; c. Reduce the amount of color ink to meet the requirements of Printability; d. At the same time, it can be printed. The text in the picture is printed with black ink, which has the best visual effect. It is not advisable to overprint the text with three-color ink

2 black version gradient setting

in color separation, the black version should be used pertinently according to the characteristics of the original and the printing conditions, as shown in Figure 1

2.1 short tone black version

when the main tone of the original is bright, and the neutral gray black and anti tone levels are less (≤ 30%), the short tone black version shall be used. The short tone black version starts from the middle tone, and the dark part can increase force by 0.4-0.7, and the dot area can reach 60%-80%. Its function is to strengthen the contrast between the middle tone and the dark tone, emphasize the darkest tone level, make the skeleton of the level, and highlight the outline of the image level, as shown in curve ① in Figure 1. The steeper you go to the dark key. It should be noted that when the short tone black version is used, the background color of the three primary color version level curve will not be removed

2.2 black version of middle note

medium light and dark color manuscript. When the area of anti tone layer accounts for about half, the black version of middle note should be used. The gradient of the black version can be extended to a high profile, and the black version can be used at about 20% of the gradient, which can not only stabilize the printing reproduction of the middle note gray, but also increase the strong sense of the dark tone level. The density of middle note black plate can be increased by more than 0.6 in the darkest tone, and the maximum point can reach 80%-95%. The printing density level curve is mostly straight, as shown in curve ②. When using the middle note black version, a small amount of background color shall be removed from the three primary color version based on the short tone black version, so as to reduce the amount of overprint of the three primary color points mixed in the neutral tone and dark tone

2.3 full tone black version

such as mechanical drawings and traditional Chinese painting originals, the medium and dark tones are mainly composed of achromatic layers. When the area of black and gray layers reaches more than 70%, full tone black version should be used. This kind of manuscript uses black edition from the high-profile of the image, which can stabilize the printing reproduction of full-scale neutral gray and improve the overprint adaptability of four color dots in the dark. Full tone black version can increase density by 1.0 ~ 1.5 in dark tone. The point area can reach 85% ~ 100%, as shown in curve ③. When using the full tone black version, based on the short tone black version, remove the background color with a large amount of full-scale blending (30% ~ 60%)

if the conditions of paper, ink, printing equipment, etc. are poor, the "background color removal" or "gray component replacement" should be used. Since the whole tone has black to color ink replacement, the full tone black version should also be used

3 generation of black version

3.1 generation of black version

the black version signal is not the result of scanning and color separation, but should be generated according to the length and depth of the original level gradation and the printing overprint requirements. In the process of photographic color separation and plate making, red and green filters can be used for exposure respectively, or amber filters can be used for one exposure to form a black plate. In the electronic color separation machine plate process, the black plate is obtained by calculating the three color separation signal. In the color desktop publishing system, there is a separate Black Edition setting and adjustment function. According to the needs of copying, you can arbitrarily adjust the parameters in "black version generation": adjust the curve shape of black version, determine the starting point, ending point and maximum point value of black version, etc. The adjustment range is large and the range is wide, which can meet the requirements of Black Edition for all kinds of original copy

(to be continued)

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