A subtractive colour model helps to make sense of what happens when different coloured pigments (eg. paints, inks, dyes or powders) are mixed together to produce other colours.
- CMYK is a subtractive colour model.
- As cyan, magenta, yellow and black (K) pigments are combined they subtract from the amount of colour reflected off the resulting mixture.
- CMYK printing typically uses white paper which has good reflective properties and then adds cyan, magenta, yellow and black ink or toner to produce colour.
- Highlights are produced by reducing the amount of coloured ink and printing without black to allow the maximum amount of light to reflect off the paper through the ink.
- Mid tones rely on the brilliance and transparency of the pigments and the reflectivity of the paper to produce fully saturated colours.
- Shadows are produced by adding black to both saturated or desaturated hues.