Non-spectral colour

A non-spectral colour is a colour that does not appear in the visible spectrum and is not produced by a single wavelength, (or narrow band of wavelengths) of light.

  • Whilst a spectral colour is a colour that is evoked by a single wavelength of light in the visible spectrum, a non-spectral colour is produced from a mixture of spectral colours from difference areas of the spectrum.
  • An example of a non-spectral colour is magenta which is produced by mixing blue and red. Blue and red are at opposite ends of the visible spectrum.
  • Whilst both spectral and non-spectral colours are produced by mixing a combination of colours (corresponding with different wavelengths of light)  from different areas of the visible spectrum:
    • The RGB colour model produces a full gamut of colours by mixing red, green and blue primary colours in different proportions.
    • The CMY colour model produces a full gamut of colours by mixing cyan, magenta and yellow primary colours in different proportions.