RGB[A] vs. CYMK

The color wheel at the left shows the relationship between RGB colors and CYMK colors. They are 60º out of phase with each other. Notice the RGB colors have a + sign and the CYM colors have a - sign.

RGB (Red Green Blue [Alpha]) refers to the color guns used on video screens. The plus sign on the color wheel graphic indicates they are "additive" colors which means the different colors of light add to each other to produce a range colors.

CYMK (Cyan Yellow Magenta Black) refers to the colors use in printing. The negative sign on the color wheel graphic indicates they are "subtractive" colors which means each color is seen because the pigment absorbs (subtracts) the other colors and reflects the visible color.

Both systems use tiny dots of pure color combined to simulate the rest of the colors. Intensity/richness changes are controlled in RGB by increasing or decreasing the intensity of the light, while in CMYK it is done by increasing or decreasing the size of the dot of pigment.

RGB is used for screens and CMYK is used for printing.