Brief analysis: The specific application Of chromatics in Cigarette Box Of Matte printing

Dec 14, 2022

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This paper will elaborate the application of colorology in printing from three aspects: the production of printing chromatography, the measurement of printing hue and the deployment of spot color ink.

1. Use chromatics to produce printing chromatography

In the whole process of color reproduction, there are three processes: color analysis, color transmission and color combination. The correct control of color change in each process is directly related to the final quality of the printed matter, so it is necessary to standardize a color standard that is printing chromatography to regulate various shades in the printing process. Printing chromatography of Shanghai Printing is the use of three primary colors yellow, magenta, cyan and black, according to different proportions or dot percentage mixed, laminated together, to form a variety of colors and patterns of the atlas, for people in the design, original copy, ink deployment and other aspects of reference.

Four-color chromatography is the use of yellow, magenta, green, black four color ink, with different dot area percentage (generally only choose 0, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100% eleven dot levels, can also be divided into 5% dot levels) overprint superposition, and according to a certain order of composition, It has important reference and guidance function for electronic color separation, proofing and printing. Spot color in printing is a kind of mixed color ink, and Y, M, C, K has no direct relationship to the color, so the first definition of a set of standard primary color ink, according to different mixing ratio to produce a variety of color color samples, each color sample is marked with a scalar representing the mixing ratio of primary color, so that people use the three primary color ink to blend a variety of color spot color. This is spot color chromatography.

At present, the international general use of Pantone company Pantone color chromatography. But printing chromatography is the color of color, its production is usually affected by ink, paper, printing technology and equipment and many other factors, so printing units should be based on the raw materials used by the factory, production technology, equipment conditions and other production of their own special printing chromatography.

2 Use chromatics to measure color and color difference

Color measurement in color printing can be roughly divided into three kinds: contrast visual measurement, density measurement and chroma measurement.

In the process of printing, contrast visual method is used to measure the color. It mainly relies on experienced operators to evaluate the color of the original manuscript, signal strip and printing sheet by contrast visual method with reference to the standard color rate. Due to the influence of the observer's own physiological and psychological factors, the accuracy of comparison visual method is relatively poor. But because it does not need to be equipped with fine measuring instruments, it is widely used in the general printing copy work.

Density measurement method is a method to measure the order and color value of color using optical density value. In the process of color printing, the density value can well reflect the proportion of primary color ink and superposition performance, and the detection equipment is simple, so it is widely used. But the optical density as the printing process monitoring and measurement means, only from the control bar to obtain the size of each monochrome ink, and can not directly obtain the color error information from the image, so it is difficult to communicate with printing customers, it is not easy to accurately control the color reproduction, so the density measurement is only an indirect color measurement method.

Chromaticity measurement method is based on chromaticity theory, with the color of the important parts of the printed image as the monitoring point, directly measure the tri stimulus value of color, obtain color chromaticity information. This method can accurately express the color difference and the desired approximation between the standard sample and the tested sample without the need to add a standard or control bar. However, it has not been popularized and popularized at present, mainly because of the high price of the instrument and the high requirement of color theory for users. As a large cigarette label printing enterprise, most of our products are involved in spot color printing. Due to the good use of chroma measurement and color control, few customers have complained about the color in the past few years.

In the work of color printing and reproduction, it is not only necessary to understand the three attributes of color, but also to understand the difference between colors, so as to compare and distinguish colors, which is color difference. The color difference is measured in NBS, which stands for National Bureau of Standards. At present, the universal color measurement standard in the world is CIE1976Lab Uniform Color Space, which was put forward by Canadian Wieselski at the 18th CIE in 1975. Where L is mental brightness, a and b are mental chroma, and the color difference is △E. When a is positive, it is red, and when it is negative, it is green. When b is positive, it is yellowish, and when B is negative, it is bluish. If L is positive, the color is lighter; otherwise, it is darker. Color difference △E is generally less than 3, color difference gives a person the feeling is not very big, but also affected by the deep, light and printing materials.

3. Use chromatics to mix special color ink

Ink is the color material of printed matter. It is a mixture of color material, binder, filler and co-solvent. It is a colloid with complex structure. Ink deployment refers to the whole process of blending one or more kinds of ink together and adding certain auxiliary materials to meet the needs of printing and color. Shanghai printing any kind of color, can be obtained by mixing different proportions of primary colors.

3.1 The color allocation of ink should follow the rule

(1) The deployment of special color ink should be carried out under the standard light source D65. If it is daytime, it can be carried out in the north window with sunlight.

(2) three color ink equal mixing, can be approximately black. If you add different proportions of white ink or diluent, you can get different shades of gray ink.

(3) The three primary colors and inks are mixed in different proportions to obtain different shades of intercolor or compound color.

(4) The two primary colors can be mixed equally to obtain the intermediate color; Mixed in different proportions, different hues can be obtained.

(5) The more color types used in color matching, the worse its brightness, adding black ink in any color ink, brightness value decreases; Add white ink, its brightness increases.

(6) Pay attention to the influence of the paper used, the color sequence of the printing set, the color of the lighting source on the ink color and the color changes before and after the printing drying.

(7) Complementary colors can be used to correct color bias, but only when the ink brightness value is high.

(8) As little as possible to use different varieties of original ink, in order to reduce the complementary effect.

(9) pay attention to the impact of ink viscosity on hue.

(10) Before the more complex spot color matching ink, you can first try a small amount of matching, determine the ratio, and then according to the ratio of the amount of ink used to avoid waste.

3.2 Deployment of dark ink

Only with three primary colors or intercolor primary ink, without any diluent to carry out ink deployment, collectively known as the deployment of dark ink. The deployment of dark ink has the following steps:

(1) Determine the primary colors contained in the original color sample and the order of the main colors, auxiliary colors and the approximate proportion of each color ink.

(2) According to the printing ink area, ink coloring force, printing plate depth, paper performance, ink viscosity, printing quantity and other factors, to determine the deployment of the quantity.

(3) According to the deployment ratio, comply with the order of large to small add ink. First weigh the main primary color with the most content, then weigh the auxiliary color with less content, and then add the auxiliary color ink into the main color ink several times, and reconcile evenly.

(4) After comparing the color and adjusting the proportion of the three primary colors, the printing suitability can be adjusted by printing auxiliary agent after meeting the original sample.

(5) Record the proportion of each primary color component, in case of reprinting or insufficient ink, to ensure the consistency of rematching ink color.