Colour Mixing
This domain tests controlled mixture: matching a swatch, building a tint/shade scale, muting a colour deliberately and choosing the right mixing sequence for the medium. Practical answers need ratios and a test procedure, not just colour names.
Core rules
- Add dark to light in small amounts; it is easier to darken than to recover a lightened mix.
- Start with the lightest pigment, then add the stronger or darker one gradually. Phthalo blue, for example, has enormous tinting strength.
- Keep recipes to two or three pigments. Beyond that, chroma collapses into mud because complementary or near-complementary pigments neutralise each other.
- To mute a colour, add its complement or a low-chroma earth such as burnt umber; to lighten without dulling, use transparent white or more water, depending on the medium.
- Dull a shadow with a complement rather than black; black can grey and flatten flesh tones.
- Judge a match against a neutral grey surround, and compare a dried test strip because water-based paint dries lighter or darker.
- Record recipes in parts, e.g. 5 yellow : 1 blue : ½ red.
Worked example
Match a mid-olive green. Begin with a warm yellow, add a little blue until the hue is green, then add a touch of red-orange to reduce brightness. Test on the same paper. If it is too blue, add yellow; if too bright, add more red-orange; if too dark, add yellow rather than white first, because white will also cool and chalk the mix. A workable starting ratio is 6 yellow : 2 blue : 1 red-orange. The reasoning is hue first, then chroma, then value.
Traps that cost marks
- Adding black to yellow to darken it, which produces a greenish, dead olive.
- Overmixing on the palette until the colour is uniform but muddy.
- Judging the wet swatch as the final colour.
- Using too much water in acrylic, which breaks the binder film.
- Failing to note proportions, so the match cannot be repeated.