Colour

Understanding colour systems for print processes

There are 2 colour processes called subtractive colour and additive colour.

Subtractive colour (CMYK): is the mixing of colours to create a range of colours, where each colour is caused by light being absorbed and relefecting colours. Subtractive colour systems start with white light. Coloured inks, paints or films are placed between the viewer and the light source or reflective surface (such as white paper) subract wavelenghts from this white, and make a colour.Subtractive colour is used in offset litho printing.

Additive colour (RGB): This process usually uses red, green and blue light to produce other colours. Combining one of these additive colours with another in equal amounts produces the additive secondary colours cyan, magenta and yellow. Combining all 3 primary colours in equal intesities produces white. Things such as, Computers, mobile phones, televisions, projectors etc that are usally screen base use this process.