RGB, Spot Colors, and CMYK: Navigating the Color Spectrum

For optimal results in your print project, it's recommended to provide files in CMYK. CMYK, the color model utilized by printers, involves applying ink to paper to create color through reflected light. In contrast, RGB is the color model used for screens, such as monitors, relying on device light to produce color.

OnPress does not offer digital book distribution, and images intended for print should be in CMYK. If RGB images are submitted for print, they'll be automatically converted to CMYK without additional warning, given the frequency of such submissions. Let's look at some examples of RGB to CMYK conversion.

RGB	CMYK

These examples are extreme to prove the point. They are some of the most vivid colors in the RGB spectrum that sit the farthest from a comparable CMYK value. These would be common if you are picking suggested colors in a Microsoft program, or perhaps children's book illustration, but usually not present in most photographs.

RGB	CMYK

This is an example of a photographic conversion. You could certainly improve the results, but this should demonstrate why you don't necessarily want to trust a computer to do your color management.

Spot colors, employed for specific hues like "Tiffany Blue" or in two-color printing scenarios, should typically be converted to CMYK unless special arrangements have been made with your printing specialist. While we can handle the conversion, results may not meet expectations, prompting further adjustments. While errors in this regard are infrequent, you may receive a warning or be asked to confirm conversion preferences.

Please note: no technology exists to print in the RGB color spectrum.