CMYK is a colour format that is more commonly used within printing as you may recognise it from countless trips to Tesco at last minute to print off that important document but the printer just so happened to have run out of black and yellow. CMYK which stands for Cyan, Magenta, Yellow and K refers to Black. The reason it’s letter is K is because it means Key colour. Most colours will have to use black unless it is a pure colour then it will only have to use the other three. There can be a few variations to this but all printers either at home and university will run on CMYK. The other option that is available is to print with pantones. You need to have special printers to be able to print with pantone colours.