CMYK is a colour model used in printing processes – Cyan, Magenta, Yellow, blacK. CMYK inks are combined with each other not by blending together, but by applying in layers, therefore the final effect may have from 0 to 400% colour coverage. In this case, combining the paints causes the colour to become darker and eventually black. This is known as subtractive mixing. Interestingly enough, setting K (black)  to 100% does not create the darkest black possible. To receive a “true” black, you need to add other colours from the CMYK model – 60% C, 40% M, 40%Y, and 100% K gives the best result.

The image on the monitor, which uses the RGB colour model, is more vibrant and has a greater colour depth. It is also caused by the fact that the monitor emits light and the paper absorbs it. RGB has a wider range of colours than CMYK. Problems with converting between CMYK and RGB colour models result from the fact that it is impossible to reproduce all the colours you see on a screen in printed ink. As a result, we not only modify but also lose some information about the colour.