What can I do with this online tool?

You can convert images from the RGB to the CMYK color space. The RGB scheme is used mainly for computer displays, while the CMYK model is used for printed color hard copies. If you want to have something printed professionally, like a postcard, brochure, flyer or business card, your printer will sometimes request your files to be submitted in CMYK mode.

What are these profiles and which should I use?

CMYK profiles describe how a color should be printed. Profiles are device dependent: each profile describes a specific press and paper type. That means that there is no "generic" CMYK profile that will suit all press conditions. You need to discuss with your print provider which profile is most appropriate.

However, if you can't get any information about the required CMYK profile, GRACoL 2013 is the current standard in the US. In Europe, it's PSO Coated v3 for coated and PSO Uncoated v3 for uncoated paper; many print shops still use their predecessor ISO Coated v2 (300%) ECI.

When I convert RGB to CMYK, the colors change?

Some RGB colors that you can see on your monitor (in particular blue, green and all bright, vibrant colors) cannot be printed or replicated with standard CMYK inks.

Can I also convert CMYK to RGB?

No, not with this service. But our sister website www.cmyk2rgb.com converts images from the CMYK color space to RGB.