You might have heard of the colour wheel.. a rainbow of colours running from red to orange, yellow, green, blue and purple.

Red, Blue and Yellow are known as primary colours. These are the ones you can mix together to get Orange (yellow and red) Purple  (blue and red) and finally Green (blue and yellow)

There are mixtures that can also make all the different colours of the spectrum.

If you know the theory of colour you also know White is all colours mixed together. This is why if you put a prism of glass in a beam of sunlight it will split the white into all of the colours of a rainbow. Newton did this experiment and helped us understand the nature if light.

On the other hand, Black is an absence of colour, all the colours that hit a black surface are absorbed, they don’t reflect back to your eyes. If you mix up all the colours of the spectrum you tend to get Brown, not as you might expect, Black.

Did you know there are complementary colours? If you spread the primary and secondary colours around a circle split into 6 equal segments you can see how the primary colours are next to one’s of a mixture of them and the next primary. So the wheel ends up with the most contrasting (complementary) colour directly opposite each other.

These are

red/green

yellow/purple

blue/orange

These colour combinations seem to sing, like a discordant chord they bounce off each other.

Some famous artists like Cezanne and Van Gogh would exploit these clashing colours to create strong images. Van Gogh’s blue skies contrasting with the orange of sunflowers makes the paintings seem to glow. Cezanne’s use of green vegetation and red soil has a similar effect.

So sometimes when I paint or draw I will chose to use complementary colours to see what I can create from them.

Of course there are other colours out there. ..the author Terry Pratchett wrote about Octarine, the eighth colour of the rainbow, I think he said it was a purplish black …..

But in reality there are colours beyond human perception. The ones nearest to the spectrum we see are Infra red, which gives heat. You need special detectors to show this colour, and also ultra violet which can cause tanning or sunburn when the uv light is strong enough.

The spectrum continues into longer and shorter wavelengths beyond infra red and ultra violet. But that’s another story….