What is CMYK?
In short
CMYK is the colour model used in printing: cyan, magenta, yellow and black (K) inks combine to make every colour on the page.
CMYK stands for cyan, magenta, yellow and key (black), the four process inks used to print full-colour work. Screens make colour from light in RGB (red, green and blue); print makes it with ink on paper. Because of that, some bright screen colours can't be matched exactly in ink.
Why it matters for your file
Set your artwork up in CMYK, using the FOGRA39 profile, before you export. An RGB file still has to become CMYK to be printed, and the brightest greens, blues and oranges usually come out duller than they look on screen. Converting first lets you see the change and adjust your colours before you order. Our free automatic check looks at the colour mode of every file you upload.
Paper changes colour too
The same CMYK values look different on different papers. Gloss and silk papers keep colours bright and crisp. Uncoated paper, like the 120gsm paper we use for letterheads and compliment slips, takes the ink into its surface, so colours look softer.
Blacks and ink limits
For large black areas, use rich black (C63 M52 Y51 K100) so they print deep and even, and keep small text in 100% black only. Keep the total ink coverage at 300% or less. Our CMYK vs RGB guide explains what to do with brand colours that shift in print.
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