The chromophore is the part of a molecule responsible for its colour.

  • Things appear to have colour because they absorb some wavelengths of light and reflect others.
  • The result of wavelengths of light within the visible spectrum entering the human eye is the experience of colour for an observer.
  • The chromophore is the region of a molecule where there is an energy difference between two separate molecular orbitals.
  • A  molecular orbital describes the location and wave-like behaviour of an electron as it travels around the nucleus of an atom.
  • If the energy difference of a chromophore falls within the range of the visible spectrum (2 to 2.75 electron volts) then it will produce colour.
  • The colour produced by a surface or object corresponds with wavelengths of light that are not absorbed during its interaction with the chromophore.