As established in the previous post, the CMYK colour process is a SUBTRACTIVE colour process. This meaning that when the colours are built up on white, they create black. The system works with inks, paints, dyes and any material form of producing colour. This is why it is a method used in printing. It is subtractive as it takes away white in order to produce colours over it. This diagram explains:
The other form of building colour is with light. This method is the ADDITIVE colour process and the system of RGB colours works through it. It is the system that computer screens work with causing a bit of a predicament when it comes to getting colours made up in the additive RGB system on screen to print in the subtractive CMYK system. However, professional design programs have developed in order to make this easier for designers such as proofing colours and checking gamut warnings on Photoshop. Photoshop is used extensively for screen based media so it works in RGB which makes it slightly annoying for when you want to produce a piece on it for print. Although there are good systems to get around this explained in a previous blog post of a tutorial. Illustrator works in CMYK as the program is primarily for print based media, which is convenient.
The process is described as additive as it uses the primary colours of light, Red, Green and Blue, to build white when they are 'added' together in darkness. This diagram shows:
Be seeing you!