When you add colours of light together, you get different colours.

The diagram below shows how you can add the primary colours of light (red, green and blue) together to make the secondary colours (cyan, magenta and yellow).

You will see in the middle that adding all the colours together makes white.

The way these colour wheels work, is that the input colours are the large outer circles, and where they cross over is where the colours have added to make a new colour.

We can also show the colour additions in the format below to show how each of the secondary colours are formed. As an example, the first row below shows how cyan light is made up of blue and green light.

If you add all the primary colours of light together, you get white light.