These refer to color modes available on your software program. RGB (red, green, & blue) are the primary colors of light. Mixing these three colors in various combinations can produce hundreds of thousands of colors of light. Computer monitors always display in RGB color mode. Printing requires ink pigment instead of light to produce color. Offset printing uses four colors – Cyan, Magenta, Yellow and Black – also known as CMYK. Similar to an artist’s palette, mixing these four ink colors can produce hundreds of thousands of colors. PMS, also known as Pantone or spot colors, are specific colored inks. PMS colors are not created by mixing CMYK ink pigments. If your artwork is created using RGB or PMS colors, our system will convert the colors to a CMYK equivalent color during the proofing process. Not all RGB and PMS colors have a CMYK equivalent, which can cause significant color changes from your original file to your proof. We recommend creating your artwork in CMYK color mode to minimize the color change.