1. Color distortion caused by color restoration processing Modern printing usually uses C, M, Y, and K four-color inks to reproduce colors. Due to the purity of the ink itself, color distortion will also occur during printing. 2. The original has color distortion Most of the printed image manuscripts are obtained by photographic means. For photo manuscripts, in addition to color distortion caused by improper operation during the shooting process, colors are reproduced by coloring materials such as coloring materials, and coloring materials are prone to color attenuation, which may also cause color distortion of the photo. In addition, with the continuous popularization of digital cameras, there are more and more digital image manuscripts, and digital cameras have greatly improved the technical requirements of the operators. Due to the poor technical level of the operators, the captured images are prone to dim pictures and blurred images. The problem caused the color distortion of the original manuscript. 3. Color separation caused by color distortion Printing usually uses C, M, Y, and K four-color inks to reproduce colors, and the image information collected by the digital acquisition device to the computer is usually R, G, and B information. Therefore, the image information needs to be converted into C, M, and M before printing. Y, K mode, that is, color separation processing. The so-called "color separation" is to decompose and convert the color information of each pixel of the image (usually R, G, B color information) into color information suitable for printing C, M, Y, and K modes. In the process of color separation, color information will be lost. In color separation, only by correctly setting the color separation parameters (such as setting dot enlargement value, gray balance parameters, black level tone, etc.) according to the printability of ink, paper, etc., can it be possible to output high-quality color separations. It is possible to reduce the loss of color information. How to distinguish color distortion After understanding the main factors of color distortion, how to find color distortion in the actual production process is the key. 1. First impression benchmark method The human eye has a certain degree of adaptability to color. For images with slightly distorted colors, repeated observation will weaken the ability to recognize. Therefore, when judging whether there is color distortion, using the first impression to eliminate the limitations of human color vision is an important method for discovering color distortion. 2. Skin color benchmark method The color of the skin is the color that people are most familiar with. Images of people, especially portraits, can be used as a basis for distinguishing color distortion based on the color of the skin. Regardless of yellow skin, white skin or dark skin, the skin color has a pattern, that is, it is bloody. Namely: there is red in yellow, red in white, or red in black. If the skin color of the person in the image is yellow, it will give people a morbid feeling. Under normal circumstances, even if the skin color of the person in the image is really yellowish, it should be adjusted to bloody when the color is corrected, that is, there is red in yellow. 3. Neutral color benchmark method There are many neutral colors in life, such as black, white, gray, etc. They are the zero point of colors in the colorful world, and we can use them as the basis for distinguishing color distortion.
