Red, Green, and Blue (RGB) are the three primary colours of light. In any light generating device (like computer screens), RGB blends these three colours to produce all other colours.
There are two types of colour profiles: additive and subtractive. RGB is an additive profile because you create new colours by adding primary colours of light together.
Green light + blue light = cyan Blue light + red light = magenta Red light + green light = yellow Red light + green light + blue light = white
With RGB, the colour gamut is very wide, so it can produce a broad range of colours. This is because it essentially mirrors how our eyes see colour. In our retinas, we have three different kinds of cone cells that pick up on red, green and blue light. Our brain then blends together the different signals that the cells receive, producing an astonishing array of colour.
Of course, this all depends on one key factor: light. Anything that’s printed doesn’t generate light, it reflects it. So, how do you reproduce colour in print, if there’s no light source?
The answer is that you don’t add, you subtract, which is where CMYK comes into play.
The RGB colour model