Colour Modes: What do RBG and CMYK mean?


We're back with the lingo, to help you understand what's going on with all the jargon. Today we're talking colour modes. Colour is suuuper important in design (of all kinds) as I'm sure you're fully aware but sometimes, the way designers talk about colour can be a little overwhelming. But, we’re here to help!

The difference between the colour modes RGB and CMYK

Colour is integrated into our everyday lives. We obsess over it for our outfits, our homes, our phone cases - colour is everything, everywhere. And, colour is created in our eyes with light, quite literally (science alert!). When light hits paper, it is absorbed. But when it hits a screen, it's reflected. This action, creates different versions of the colours we know and love, and that's why we have different colour modes, namely CMYK and RGB! The way colour shows up on a computer will look way different than how it is printed, so by recognizing and understanding the difference, we can use them correctly.

CMYK and RGB, the two different kinds of colour models or mode, are named for the colours that make them. It’s very literal and once you know what's what, it’s easy to remember. CMYK is the colour mode used for printing, and RGB is the colour mode used on screens. Remember that, and you're good to go!

RGB Colour

RGB = red, green, blue 

RGB colours are known as additive colours, because the colours are being added together to make other colours. When all the colours are added together, the outcome is white!

CMYK Colour

CMYK = cyan, magenta, yellow, and black

CMYK works in an entirely different way to RGB. Instead of functioning like an additive model, it uses subtractive colours. CMY colours are controlled (or subtracted) to determine how much red, green and blue light will be reflected on white paper. When all colours are subtracted, the outcome is white. When none of the colours are subtracted, the outcome is black. However, black ink was added in to the print process as a standalone ink to save costs (much cheaper than mixing three colours together to print black) and was able to produce a deeper black tone.

(The “k” stands for "key”, which, traditionally, was the plate that held the image in past printing processes.)



To make it easy, anything online or digital should always be in RGB and printed material should be in CMYK. This is because monitors emit light, while paper absorbs light. Computer monitors show colour as red, green, and blue light at a low-medium resolution of 72-75 dots per inch. Print production usually requires the four colour process CMYK in high resolution of at least 300 dpi.

Finally, it’s important to remember to convert web files from RGB to CMYK if it’s going to be printed. Printers who accept RGB files convert that image to CMYK. They’re taking the colour mode not meant to be printed, and converting it which can result in faded, dull, or inaccurate colour representation in the final project- ugh! So, converting your file to CMYK gives you better control over the final image outcome.