Theory of Colours
Domain 4: Theory of Colours
This domain tests precise colour vocabulary and the ability to construct and justify colour schemes. Questions ask you to distinguish hue, value and saturation, to identify harmony types, and to explain optical effects rather than simply name colours.
Foundations
In pigment (subtractive) work the traditional primaries are red, yellow and blue; secondaries are orange, green and violet; tertiaries mix a primary with a neighbouring secondary. In light (additive) the primaries are red, green and blue; printing uses cyan, magenta, yellow and black. Hue is the colour name, value is its lightness or darkness, and saturation or chroma is its purity. A tint adds white, a shade adds black, and a tone adds grey or a complement. Warm colours (red, orange, yellow) appear to advance; cool colours (blue, green, violet) recede.
Schemes and effects
Complementary pairs sit opposite on the colour wheel: red–green, yellow–violet, blue–orange. Analogous colours are neighbours. A split-complementary uses one hue plus the two neighbours of its complement. A triad uses three evenly spaced hues. Simultaneous contrast makes a colour appear changed by its neighbour; staring at red then looking at white produces a green afterimage. Chevreul's law underlies this. Optical mixing lets small adjacent marks blend in the eye, as in Seurat's pointillism. Munsell organises colour by hue, value and chroma.
Worked example
For a poster needing tension, choose red and green. Equal areas at equal value vibrate and hurt readability. Reasoning: complementary hues intensify each other, so vary value and area - a large muted green with a small saturated red accent - and keep text on a neutral.
Traps
Do not confuse additive and subtractive primaries; do not use 'shade' for value; do not assume black is needed for shadows - complementary mixing creates richer darks.