Colour

Colours are often made of other colours. White light contains red, blue and green light, and you can divide out these colours using a prism (or looking at a rainbow). The absence of all colour is black. Red, blue and green are called the primary colours, and you get other colours by combining them in various ways. The more colour you have, the paler it gets, and closer to white. This is called Additive Colour.
The following webpage allows you to try combining additive colours to see what you get.

Combine light to make colours (additive)


However, usually we create colours with paint. Here, we start with white paper, and the more paint we add, the darker the colour gets. The basic colours for paint are not red, blue and yellow, but magenta (pinkish mauve), cyan (pale turquoise) and yellow. This is why when you mix blue and yellow paint, you don't get green. You should mix cyan and yellow. Paint works by absorbing some colours and reflecting others. So if you look at blue paint in white light, the paint absorbs all colours in the white light except blue, which it reflects. If you add other colours, then more and more light gets absorbed, and less reflected, so it gets darker. This is called Subtractive colour. In real life, when mixing paint, children usually end up with brown! It's easier with a computer.
The following webpage allows you to try combining subtractive colours to see what you get.

Mix paint to make colours (subtractive)

This is all rather complicated, so here is a simple version for younger children.

Mix paint to make colours (simple version)


These webpages used to be a different format, and I have had a request for the old format, so here they are!

Combine light to make colours (additive) - old version

Mix paint to make colours (subtractive) - old version


My name is Jo Edkins - index to all my websites - any questions or comments, email jo.edkins.science@gwydir.demon.co.uk

© Jo Edkins 2004