Colour Theory for Painting: Colour Wheel, Complementary Colours and Temperature

Colour theory for painting is mainly about understanding how colours relate to each other: which colours you can mix from others, which make each other glow, and how to calm a colour down deliberately. If you know the colour wheel, complementary colours and the difference between warm and cool tones, you will mix more confidently and paint more harmonious pictures.

In this article I explain the key basics of colour theory so that you can apply them straight away at the palette – with practical exercises for acrylic and oil.

The colour wheel: the basis of colour theory

The colour wheel arranges colours so that their relationships become visible. For painting practice, a twelve-part colour wheel as popularised by Johannes Itten is enough.

Primary colours

Yellow, red and blue are the primary colours of painting. In practice, many painters work with two versions of each – a warmer and a cooler one, such as ultramarine and phthalo blue – because this gives cleaner mixtures.

Secondary and tertiary colours

Mixing two primaries gives the secondary colours: yellow and blue make green, blue and red make violet, red and yellow make orange. Mixing a primary with a neighbouring secondary gives tertiary colours such as yellow-green or blue-violet.

Complementary colours: opposites that glow

Complementary colours sit opposite each other on the colour wheel: red and green, blue and orange, yellow and violet. Placed side by side, they intensify each other – the complementary contrast. Mixed together, they neutralise each other into broken greys and browns, which is exactly what makes them so useful.

Breaking and toning colours

Many beginners paint straight from the tube, and the result often looks garish. Most colours in nature are broken, slightly greyed. Add a little red to a green and it becomes calmer and more natural; a touch of orange calms an intense blue. Lighten with white, but rather than darkening with black, which quickly makes colours muddy, use a dark neighbouring or complementary colour.

Warm and cool colours

Yellow, orange and red feel warm; blue, turquoise and blue-green feel cool. Every colour also has warmer and cooler versions: lemon yellow is cooler than cadmium yellow. Warm colours seem to come forward, cool colours recede – the basis of aerial perspective. In portraits, too, light and shadow differ not only in value but also in temperature.

Practical exercises

1. Your own colour wheel: paint a twelve-part wheel using only three primaries.
2. Complementary scale: mix from pure blue to pure orange in seven steps. The neutral grey in the middle is your most valuable shadow tone.
3. Temperature study: paint a simple object, such as an apple, once with warm light and cool shadows and once the other way round.

For material tips, see Oil painting for beginners: the right materials and the comparison Oil or acrylic. How warm and cool contrast works in a night scene is shown in Painting a winter landscape in acrylics.

Frequently asked questions

How many colours do I need to start?

A warm and a cool yellow, red and blue plus titanium white let you mix almost any tone. Ochre and umber are useful additions.

Why do my mixtures turn muddy?

Usually too many colours were mixed, or black was used for darkening. Mix from two, at most three colours.

Does colour theory apply to both acrylic and oil?

Yes, the basics are the same. Acrylic dries slightly darker, so take that into account when mixing.

Conclusion

Colour theory is not dry theory but a tool: the colour wheel shows you mixing routes, complementary colours make your painting glow or calm it down, and warm and cool tones create space and light. Want to try it out together with me? In my painting courses and workshops all materials are provided, and I will show you right at the palette how to mix your colours.