CMYK is an acronym for Cyan, Magenta, Yellow, and Key (Black) the four ink colours used in traditional four-colour printing. This process is known as subtractive colour mixing, where colours are created by subtracting varying degrees of light reflected from the paper.
Designs created for screens use the RGB colour model (Red, Green, Blue), which is based on light emitted by displays. RGB is ideal for digital content but is not suitable for print.
CMYK, on the other hand, is designed specifically for physical printing. It offers a more accurate representation of how colours will appear on paper, allowing for greater control over the final output.
If you submit artwork in RGB, it will be converted to CMYK before printing — often resulting in unexpected colour shifts or duller tones. For this reason, it’s essential to design and export artwork in CMYK when preparing for print.