GB refers to the primary colors of light, Red, Green and Blue, that are used in monitors, television screens, digital cameras and scanners. CMYK refers to the primary colors of pigment: Cyan, Magenta, Yellow, and Black. These are the inks used on the press in “4-color process printing”, commonly referred to as “full color printing”.
The combination of RGB light creates white, while the combination of CMYK inks creates black. Therefore, it is physically impossible for the printing press to exactly reproduce colors as we see them on our monitors.
Many programs have the capability to convert the layout/images from the RGB color space to the CMYK color space. We request that you convert your colors from RGB to CMYK if your tools allow you to. By doing it yourself, you have maximum control over the results.You may notice a shift in color when converting from RGB to CMYK. If you do not like the appearance in CMYK, we recommend that you make adjustments while working in CMYK (usually lightening). Generally, you should specify CMYK color builds that look a little lighter than you want, since the dots of ink “fatten up” on press, giving you more pigment on paper than you see on your monitor. Be especially careful to keep backgrounds light if there is black or dark colored text over it, so that the text remains readable. See our RGB and CMYK Information page for more details.