The main factor that causes color distortion

1. Color distortion caused by color restoration processing

Modern printing usually uses C, M, Y, K four-color inks to reproduce colors, and due to the purity of the ink itself, color distortion will also occur when printing overprint.

2. Color distortion caused by color separation

Printing usually uses C, M, Y]]]]], K four-color ink to reproduce color, and the image information collected by digital acquisition equipment to the computer is usually R, G, B information, so the image information needs to be converted into C, M, Y, K mode before printing and plate making, that is, color separation processing. The so-called "color separation" is to decompose and convert the color information of each pixel of the image (generally R, G, and B color information) into color information suitable for printing C, M, Y, and K modes. Color information is lost during color separation. In the process of color separation, only by correctly setting the color separation parameters (such as setting dot expansion value, gray balance parameters, black plate tone, etc.) according to the printability of ink, paper, etc., can it be possible to output high-quality color separations and reduce the loss of color information as much as possible.

3. The original manuscript has color distortion

Printed image manuscripts are mostly obtained by photographic means. For the original photo, in addition to the color distortion caused by improper operation during the shooting process, the color is reproduced through the color material such as pigments, and the color material is easy to cause color attenuation, which may also cause the distortion of the color of the photo. In addition, with the continuous popularization of digital camera, there are more and more digital image originals, and the technical requirements of digital cameras for operators are greatly improved, due to the poor technical level of operators, the images taken are prone to problems such as dim pictures, blurry images, etc., resulting in the color distortion of the originals.

4. Color distortion caused by scanning processing

The image density of the original photograph is continuous, and the image information needs to be collected into a computer. When scanning an image with a scanning device, it is necessary to divide the image into discrete pixels, and collect the R, G, and B information of each pixel on the original point by point, line by line. In the scanning process, the loss of pixel color information will be caused, and image processing is based on the collected image information, and all color operations are carried out on this basis, and the color information of the image cannot be increased. Therefore, for photo originals, scanning is a very critical part of image processing, and improper operation will cause image color distortion.

How to identify color distortion

Once you understand the main factors of color distortion, how to detect color distortion in the actual production process is the key.

1. Impression benchmark method

The human eye has a certain adaptability to color. For images with slightly distorted colors, repeated observation can impair the ability to recognize. Therefore, when judging whether there is color distortion, it is an important method to use the impression of a glance to eliminate the limitations of human color vision.

2. Neutral color reference method

There are many neutral colors in life, such as black, white, gray, etc., which are the zero points of colors in the colorful world, and we can use them as the base point for distinguishing color distortion.

3. Skin color benchmark method

The color of the skin is a familiar color, and all images of people, especially those based on portraits, can be used as the basis for distinguishing color distortion according to the color of the skin. Whether it is yellow, white or dark, there is a pattern of skin color, that is, it is all blood. That is, red in yellow, red in white, or red in black, if the skin tone of the person in the image is yellowish, it will give people a sickly feeling. Under normal circumstances, even if the color of the person's skin in the image is really yellowish, it should be adjusted to blood color when color corrected, that is, yellow with red.