Color reproduction in the hottest printing

2022-08-12
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Color reproduction in printing (Part 2)

color method and subtractive method

Image some types of foamed plastic packaging can be recycled in Rhode Island. The colors in the are ever-changing and diverse, and at most four colors are used in the printing process to copy all the colors in the image. How is this achieved? This is a unique technology in our printing process. The colors in the image are decomposed before printing, and then synthesized during the printing process. In order to understand the color decomposition and synthesis in the image in the printing process, we must first understand the three primary colors of color and light and the three primary colors of pigment

trichromatic light

according to Newton's dispersion experiment, when white light passes through a prism, it will form chromatographic bands of red, orange, yellow, green, green, blue and purple, which shows that white light is a kind of compound light, which can be decomposed

on the other hand, because the formation of color is related to the human eye, according to anatomy, there are three kinds of optic nerves that can sense blue, green and red respectively on the optic membrane of the human eye. When the above three kinds of light enter the human eye, the optic nerve is stimulated and feels color, that is to say, the color seen by the human eye is related to blue, green and red

experiments have proved that all colors in nature can be reproduced according to the different proportions of blue, green and red. So in chromatics, we call blue, green and red the three primary colors of color and light

all colors in nature can be synthesized by using these three wavelengths of light, that is, different colors of objects only include the synthesis of blue, green and red lights in different proportions. This is called chromatic addition

when two or more colored lights are mixed with each other, another colored light can be obtained, which is called colored light additive method

when the blue, green and red phases of the three primary colors are mixed in equal quantities, blue (c), magenta (m) and yellow (y) with high brightness can be obtained respectively. When the blue, green and red are added in equal quantities, white (W) can be obtained. The color equation is as follows: B + g=c, B + r=m, G + r=y, B + G + r=w

in the above color synthesis equations, all colors in nature can be obtained by changing the proportion of any primary color light

printing is to make full use of the characteristics of the three primary colors of color and light, and use three color filters that can only pass through blue, green and red light to realize the decomposition of all colors on the original

pigment subtraction method

for printed matter, if the human eye can perceive the color of its surface, it must irradiate white light (blue, green, red) on the surface of the printed matter before it can be seen. That is to say, when we feel the color on the printed matter, white light irradiates the surface of the printed matter, and then through the selective modulation of the light on the surface of the printed matter, the modulated light is reflected into the human eye to produce an optic nerve impulse into the brain, Color is formed by the brain. In other words, the color of printed matter is the result of the absorption of some light in white light. According to the principle of pigment subtraction method, we only need to use three substances that can absorb blue, green and red respectively. By controlling the amount of these three substances to control the amount of blue, green and red primary color light respectively, we can realize the reproduction of object color. Substances that control the amount of light in the three primary colors of blue, green and red are called pigments. It is precisely because they can absorb the three primary colors of blue, green and red. Therefore, under white light, these three pigments reflect or transmit green and red, blue and red, blue and green respectively. After entering the human eye, they show yellow (y), magenta (m) and cyan (c) respectively, which are just the complementary colors of the three primary colors of color and light. Therefore, they are called cyan (c), magenta (m) and yellow (y) as the subtractive primary colors of pigments. This method of color synthesis is called pigment subtraction

since white light can be simply regarded as the result of equal mixing of blue, green and red primary colors, if we subtract one, two and three different proportions of primary colors from white light, we can obtain any color in nature. The so-called pigment subtraction method is a method of subtracting one or more primary colors from white light to obtain another color light. We call this method pigment subtraction method. The equation of color formed by pigment subtraction can be expressed as follows: C + m=b, C + y=g, M + y=r, C + m + y=k (black)

printing is based on this principle to complete color printing. The pigments used in printing, which are expected to achieve an annual operating revenue of 5.613 billion yuan, are yellow (y), magenta (m) and cyan (c), namely y ink, m ink and C ink. Among them, y ink can absorb B primary color light, m ink can absorb g primary color light, and C ink can absorb r primary color light

decomposition and synthesis of color

in the process of color printing, the reproduction of color is essentially a process of "decomposition" and "synthesis" of color. No matter how complex and rich the colors on the screen of any manuscript are, from the perspective of color science, the colors of each point on the screen are a combination of three primary colors in a certain proportion. Color decomposition is to use R, G, B three color filters to separate the colors in each point of the picture from the mixed state, and form a monochrome image of their distribution in the picture. Color synthesis is to use the three monochrome images obtained from decomposition to make a printing plate, and then print the yellow, magenta and cyan inks onto the substrate step by step to reproduce the color image on the original. In these two processes, light and color are indispensable from beginning to end. In lithography, in order to reproduce the color on the original, the color on the color original should first be divided by means of photographic color separation, electronic color separation or scanner color separation. BASF developed a "new material" solution. The color image on the original is decomposed into three color separation negative pictures of cyan, magenta and yellow through three color filters of R, G and B. Next, we will use eight color blocks of yellow (y), magenta (m), cyan (c), red (R), green (g), blue (b), white (W) and black (k) to represent the original, and explain the decomposition and synthesis of colors in the printing process according to the offset printing process

four color printing 5. The main bearing of the dynamometer is not allowed to refuel

in the actual printing, because the blackness shown by the superposition of yellow, magenta and cyan inks is not enough, in order to strengthen the blackness of the dark part of the image, a black plate is added for printing. Therefore, in the color printing, it is not 3-color printing, but 4-color printing, but only y, m and C colors are needed for color reproduction

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