Colour Models

Primary Colours

Primary colours can be split into two types, additive and subtractive.

The additive primary colours are red, green and blue, and form the RGB colour model, which corresponds with the three colour receptors of the human eye. These primary colours are made of pure light and produce the brightest and most intense colours.

Subtractive primary colours can be further subdivided into printers and artists primary colours. Printers primary colours consist of cyan, magenta and yellow, and form the CMY colour model. The artists primaries form the RYB colour model, which are made up of red, yellow and blue. Both sets of subtractive primary colours are made from reflected light. The RYB model is the basis of most colour theory, which consists of principles that can be used to create harmonious colour combinations.

RGB Colour ModelRGB Model

When producing graphics for use on computer screens, such as those used on websites, the RGB (Red, Green, Blue) or additive colour model is used. These pure hues, when combined produce other colours, red and blue produce cyan, red and green produce yellow, green and blue produce magenta, and finally, a combination of all three colours produces white.

CMY Colour ModelCMY Model

When producing graphics for printed material, such as brochures and books, the CMY (Cyan, Magenta, Yellow) colour model is used. The inks and dyes used in this model are transparent. CMY is combined with black, known as K, to make CMYK, which is how this model is referred to in software such as Adobe Illustrator and InDesign. The black is produced by combining the three primary colours in this model, cyan, magenta and yellow. As with the RGB model, when two of the primary colours are combined, they produce a third, cyan and magenta produce blue, magenta and yellow produce red, and, cyan and yellow produce green

RYB Colour ModelRYB Model

The RYB (Red, Yellow, Blue), or Artists Colour Model, as it is also known, is the second of the subtractive colour models, which uses opaque pigments and, as its alternative name suggests, is used by artists. As with the CMY model, combining all three primary colours produces black. Similarly, combining two of the colours produces a third, red and yellow produce orange, yellow and blue produce green, and, red and blue produce purple. As previously mentioned, this colour model forms the basis for colour theory.