Color Information
Color - The most critical part of any major printing project
CMYK printing (cyan, magenta, yellow, and black) is the color standard of the print industry. The reason printing uses CMYK comes down to an explanation of the colors themselves. CMY will cover most lighter color ranges quite easily, compared to using RGB. However, CMY by itself can't create very deep dark colors like "true black," so black (designated "K" for "key color") is added. This gives CMYK a much wider range of colors compared to just RGB inks.
The use of CMYK for printing has become kind of a trope for printers. But the reason why printing uses CMYK isn't that well known, even to many graphic designers.
On the surface, it doesn't seem to make sense. You might have learned in elementary school that the primary colors are red, green, and blue (RGB) from which all the other colors are made. After all, monitors, projectors, and television sets use red, green, and blue (RGB) to create all the other colors. Mixing some of these colors produces the secondary colors - cyan, magenta, and yellow. Mixing them all produces white.
But red, green and blue only work well as primaries for sources that emit light—like monitors, projectors, and even the sun. CMYK is used on objects that reflect light—like printed pieces—to filter certain colors from the white light source and reflect back selected colors.
We require that you convert your project from RGB to CMYK, if printing inks will be CMYK, when supplying files for print. The apparent color change from RGB to CMYK can be dramatic in many cases, such as when your artwork has a lot of bright red in it. If you desire the best possible color accuracy on your final prints, you will want to consistently set the color models for your design files before submission. This may be critical in cases where brand colors have been specifically set to a color hex code and color swatch. In these case, yes--you should definitely make sure you have set the correct color models.