Little knowledge of color, how much do you know?

Color occupies an important position in printing, which is an important prerequisite for visual impact and appeal, and an intuitive factor that attracts consumers’ attention and even triggers purchase.

spot color

Each spot color corresponds to a special ink (except yellow, magenta, cyan, black), which needs to be printed by a separate printing unit on the printing press. There are many reasons why people use spot colors in print, highlighting a company’s brand image (such as Coca-Cola’s red or Ford’s blue) is one of them, so whether a spot color can be accurately reproduced will not matter to customers or to customers. It is crucial for the printing house. Another reason may be the use of metallic inks. Metallic inks usually contain some metallic particles and can make the print appear metallic. In addition, when the color requirements of the original design exceed the color gamut range that can be achieved by yellow, cyan, and black, we can also use spot colors to supplement.

color conversion

When we convert the color of an image from RGB to CMYK, there are usually two methods to generate halftone dots of black ink, one is under color removal (UCR), and the other is gray component replacement (GCR). Which method to choose depends mainly on the amount of yellow, magenta, cyan and black inks that will be printed in the image.

“Background color removal” refers to removing a part of the neutral gray background color from the three primary colors of yellow, magenta, and cyan, that is, the approximately black background color formed by the superposition of the three primary colors of yellow, magenta, and cyan, and replacing it with black ink. . Undertone removal primarily affects the shadow areas of the image, not the colored areas. When the image is processed by the method of removing the background color, it is easy to appear color cast during the printing process.

The gray component replacement is similar to the background color removal, and both use black ink to replace the gray formed by overprinting the color ink, but the difference is that the gray component replacement means that the gray components in the entire tonal range can be replaced by black. Therefore, when the gray component is replaced, the amount of black ink is very small, and the image is mainly printed by color ink. When the maximum replacement amount is used, the amount of black ink is the largest, and the amount of color ink is correspondingly reduced. Images processed with the gray component substitution method are more stable during printing, but their effect also depends to a large extent on the ability of the press operator to adjust the color.


Post time: Jul-28-2022