CMYK vs RGB: Which Colour Mode to Use for Printing

CMYK is the colour mode for printing and RGB is the colour mode for screens. CMYK builds colour from cyan, magenta, yellow and black ink on paper; RGB builds it from red, green and blue light on a display. Send print files in CMYK so the colours you approve are the colours that come off the press. This guide explains why screen colours shift when printed, how to convert a file to CMYK, and when the difference actually matters.

What is the difference between CMYK and RGB?

CMYK is a four-ink colour model for printing, built from cyan, magenta, yellow and black on paper. RGB is a light-based model for screens, built from red, green and blue. Print presses lay down ink, so print files should be in CMYK.

Why do my colours look different when printed?

Screens emit light and can show bright, saturated colours that ink on paper cannot reproduce, especially vivid blues, greens and neons. When an RGB file is converted for print, those out-of-gamut colours shift to the nearest CMYK ink mix, so the print can look slightly duller than the screen.

How do I convert an RGB file to CMYK for printing?

In design software such as Illustrator, InDesign or Photoshop, set the document colour mode to CMYK before you export, or export a print-ready PDF using a CMYK profile. Review the file after converting, because bright RGB colours can shift, and adjust them if needed.

Which colour mode should I use for a print file?

Use CMYK for anything going to print, and keep RGB for web and screen use. If you send us an RGB file we convert it to CMYK during prepress and proof it, but converting it yourself first lets you see and approve any colour shift before printing.

Does CMYK matter for a black-and-white print?

For true black-and-white work, build the file in greyscale or use black (the K channel) only, rather than a mix of all four inks. A rich black made from all four inks can look heavy and can register slightly off on small text.

CMYK vs RGB at a glance

Getting print-ready colour from CDM Print

Whatever mode your file arrives in, we colour-manage every job against ICC profiles and send a proof before printing. Ready to print? Our business cards, colour posters and flyers all print full colour in CMYK on our presses at 4119 boul. Saint-Laurent in Montreal.