Let us explore why this lack of CMYK or spot color support is a problem. After all, you can print OG files to a color printer and the output usually looks great. Why then does the RGB color space of OG files cause problems for expensive, high-resolution output devices but not to cheap desktop printers?

Commercial offset print publishing works in one of two different ways. For full color work the four process inks, Cyan, Magenta, Yellow, and Black (CMYK) are combined to form images or color builds. These four colors can be combined to form approximately 3000-5000 different color combinations. Sometimes extra colors, commonly called Spot colors, are added. Sometimes these Spot colors are used independently in one, two, or three color jobs. For most printing companies, the only options are to print CMYK and/or Spot colors. Therefore, all colors in an electronic submission should either be Spot or CMYK as is appropriate. So, if a vendor is going to output your OG file in a normal prepress environment the RGB data must be converted to CMYK or spot as necessary. It is this conversion that causes problems.