white light

Mixture of many colours of light. If white light is passed through a prism, a band of colours called a spectrum is produced. This splitting of white light into its component colours is called dispersion. The order of the colours within the spectrum is always the same. A second inverted prism placed next to the first can be used to reverse the process, combining the coloured lights to make white light.

In 1666 Isaac Newton first proposed and demonstrated that white light was made up from a mixture of coloured lights.