Analysis of Coloring Principle of Color Printing
Color printing is simply the reproduction of images or words in color. What is the coloring principle of color printing?
1. Four color printing is to use subtractive three primary colors (yellow, magenta, cyan) and black for printing. The printing process that uses ink other than yellow, magenta, cyan and black to copy the original color is called "spot color printing" or "spot color printing". It is a lithographic printing method that uses red, green, blue primary colors and black pigment (ink or fuel) to realize full color reproduction according to the principle of subtractive mixing.
2. Primary colors (CMYK, RGB)
a. CMY uses white as the background color, that is, CMY is 0, white, and black (but in practice, due to the purity of the ink and other problems, pure black cannot be obtained, so K is introduced) Answer supplement
CMYK color mode is a printing mode. The four letters refer to Cyan, Magenta, Yellow and Black respectively, representing four colors of ink in printing. In essence, CMYK mode is no different from RGB mode, but the principle of color generation is different. In RGB mode, the color light emitted by the light source is mixed to generate color, while in CMYK mode, the light that shines on the paper with different proportions of C, M, Y and K inks, after part of the spectrum is absorbed, the light reflected to the human eye generates color. When C, M, Y and K are mixed into color, with the increase of C, M, Y and K, the light reflected to the human eye will become less and less, and the brightness of the light will become lower and lower. All CMYK mode color generation methods are also called chromatic light subtractive method.
b. Accurately speaking, RGB belongs to the three primary colors of color and light. Its color formation principle is to realize the color formation of light source by controlling the light. The light source peripherals are mainly displays, scanners, projectors, etc. CMYK and RGB both belong to mixed and composite colors, and both depend on the color space of the device. RGB tricolor mixing presents white, which is called additive mixing; CMYK three primary colors are mixed to show black, which is called subtractive mixing.
3. Spot color
Spot color printing is an ink that provides spot colors based on different color requirements. Some spot color inks contain colors that cannot be obtained with four primary colors, such as silver, gold, fluorescent and some bright colors. The ink prepared by spot color printing is used to obtain color according to the mixing principle of pigment subtractive method. Its color brightness is low and its saturation is high. Spot color blocks with uniform ink color are usually printed on the spot, and the amount of ink should be appropriately increased. When the thickness of the ink layer is large, the sensitivity of the change of the ink layer thickness to the color change will be reduced, so it is easier to obtain a uniform and thick printing effect.
