The Differences Between RGB and CMYK Colour Modes

For those unfamiliar with colour modes in design, here is a guide to help explain the differences between the two colour modes used in design: RGB and CMYK.

RGB is the acronym for Red, Green, Blue and it’s the colour mode based on light that is used on screens and projecting. CMYK is the acronym for Cyan, Magenta, Yellow and Key (Black) and is based on ink, so it is used on printing.

How do the colours work?

With RGB, values range from 0-255 for each red, green and blue. RGB is an additive colour process, so when all values are at 0, you get black, while when the all values are at 255 you get white.

With CMYK, values range in percentages, so 0 – 100% for each cyan, magenta, yellow and black. CMYK is a subtractive colour process, which means that when you mix 100% of cyan, magenta and yellow, you get black. Key (or Black) is included in the process for two reasons: firstly, to save using all three inks to make black and secondly, it produces a richer black.

So in a nutshell, adding all the colours together in RGB gives you white, while adding all the colours together in CMYK give you the opposite: black.

RGB has 16,777,216 colour potentials, while CYMK has 1 million colour variants.

Colour mode

When to use?

RGB should be used for any work that will be viewed on a screen or projector. Therefore, for graphics that are digital and used on online media (websites, social media, e-mails etc), animations, film, presentations and software user interfaces will use RGB.

CMYK should be used for any work that will be printed. Examples of this would be posters, books, magazines, brochures, billboards, newspapers, business cards and any other traditional print media.