An introduction to colour theory

Posted by Sarah Jane Humphrey on

Who finds mixing colours a challenge?

I always think mixing colours is a little like cooking – some people will instinctively be able to pair flavours (or colours), and others will not know where to start. If you don't feel like you possess the natural ability to mix colours it can be daunting. However, there's good news – it needn't be. There is a science to colour and with a little practice you will soon discover how to make decisions on which ones to use. Learning the basics will help you to comprehend the properties behind colours and the results you can achieve from skilled observation and mixing, aiding you greatly in your artwork.

Colour in its simplest form

Colour is a property of light – a sensation conveyed by our brain when looking through our eyes. To truly understand colour theory you first must go back to how colours are split and segregated into groups. This goes back many years to the connection English physicist Sir Isaac Newton (1642-1727) made between colour and light. In 1666, Newton made the discovery that shining a white light through a prism separated the beam into seven different colours. These 'spectrum colours' are made up of red, orange, yellow, green, blue, indigo and violet (otherwise known as ‘rainbow colours’) and are the colours visible to the human eye. Newton also discovered that white light is a fusion of these coloured lights. From here, Newton put the spectrum colours in formation in a circular colour wheel. This early theory became the basis for future artists to build upon to improve the comprehension of colour. 


Colour Wheel

Colour Wheel


Primary and Secondary Colours

The German artist Jakob Christoffel Le Blon (1667-1741) took Sir Isaac Newton’s theory a step further by discovering the three ‘primitive colours’: red, yellow and blue. Now known as 'primary colours', Le Blon realised that these three colours are all that is requited to mix all other colours. He also recognised that by mixing the three primary colours together you can make black.

The secondary colours are those made when mixing just two of the primary colours together. This can be really useful to understand how to mix your own colours. You will notice how you can make each secondary colour from using equal quantities of paint. The next steps are to explore what happens when you start changing the amounts of each pigment. For example, using a tiny touch of red paint with more yellow will make a brighter yellowy orange compared to a darker colour when using a touch of yellow with more red. Below is a simple colour study which explores this. 

Colour theory 

Mixing primary colours to make secondary colours
Red + Yellow = Orange
Yellow + Blue = Green
Blue + Red = Purple
Red + Yellow + Blue = Black


Colour Study

Complementary Colours

In the 20th century, Swiss born expressionist artist Johannes Itten (1888-1967) took things a step further again, by pairing colours. Otherwise known as 'complementary colours', these pairs cancel each other out when mixed together, to create a grayscale colour like black or white. Itten adapted Newton's colour wheel to include 12 hues, placing these complementary pairs opposite one another.

When using these pairs in artwork, the juxtaposed colours work together harmoniously. However, they can also be mixed together in varying quantities to tone one another down. The best way to do so is to combine very small amounts of complementary colours together in order to successfully add shadow or different tones. An excellent way to practice is by using this technique to paint green leaves (green is a notoriously difficult palette to get correct). By carefully adding thin layers of different colours you can create a whole range of shades. This is demonstrated in the exercise below, whereby with the addition of other colours from the wheel, and varying amounts of water, a selection of colours with varying depths can be created.  Remember, it's always best to do this on a test piece of paper first, before adding colour to the piece of art you're working on.


Complementary colours
Red - Green
Orange - Blue
Yellow - Purple

Green palette

The green palette



In summary, whilst colour can seem daunting when approaching a piece of art, there is a science through which it can be learned. The basic principles mentioned above are a good starting place for understanding colour and how different types of colours react with one another. Over the coming months, we will be exploring colour more via the blog. But until then, please don't hesitate to share your thoughts and questions. 

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