Why Colour Theory Matters
Walk into any art-supply shop and you will find hundreds of paint colours lined up on the shelves. It is tempting to buy one of everything, but the truth is that a handful of well-chosen pigments will take you further than a drawer full of tubes you never open.
Understanding how colours relate to one another helps you mix cleaner hues, create mood, and avoid the dreaded "mud" that happens when too many pigments collide on the palette.
Primary, Secondary and Tertiary
In paint mixing (subtractive colour), the three primaries are red, yellow and blue. You cannot mix them from other colours, but you can mix nearly everything else from them.
Combine any two primaries and you get a secondary colour: red + yellow = orange, yellow + blue = green, blue + red = violet. Mix a primary with its neighbouring secondary and you land on a tertiary — red-orange, yellow-green, blue-violet and so on.
This twelve-step wheel is the backbone of every colour decision you will make.
Warm and Cool
Every pigment leans warm or cool. Cadmium Red is a warm red (it tilts toward orange), while Alizarin Crimson is a cool red (it tilts toward violet). The same goes for yellows and blues.
Keeping a warm and a cool version of each primary on your palette gives you the cleanest secondaries. Want a bright, punchy orange? Mix a warm red with a warm yellow. Need a delicate violet? Reach for a cool red and a cool blue.
Complementary Colours
Colours that sit opposite each other on the wheel — red and green, blue and orange, yellow and violet — are called complementaries. Placed side by side they vibrate with energy and draw the viewer's eye. Mixed together they neutralise each other, producing a range of greys and earth tones that are far more interesting than anything from a tube.
Next time you want to darken a colour, try adding a touch of its complement instead of reaching for black. You will get a richer, more natural shadow.
Building a Limited Palette
A solid starting palette needs just six tubes: a warm and cool version of each primary. For watercolour, a good set might be:
- Warm red — Cadmium Red or Pyrrol Scarlet
- Cool red — Quinacridone Rose or Alizarin Crimson
- Warm yellow — Cadmium Yellow or New Gamboge
- Cool yellow — Lemon Yellow or Hansa Yellow Light
- Warm blue — Ultramarine Blue
- Cool blue — Phthalo Blue (Green Shade) or Cerulean
From these six you can mix almost any colour you will ever need. Add a Burnt Sienna for convenience and you are set for landscapes, portraits and still-life work.
Practise on Purpose
The best way to learn colour mixing is to make colour charts. Squeeze out your six primaries and systematically mix each pair, recording the ratios and the pigment names. Tape the chart above your workspace. Within a few weeks you will reach for the right tube automatically, without thinking.