Color difference formula adopted by the Colour Measurement Committee of the Society of Dyers and Colourists of Great Britain in 1984. It describes color differences in the CIE LCh color space.

This formula uses an equation (l:c) which allows the setting of lightness and chroma factors. Most common are the following factors:

• dE CMC 1:1

  Equal weighting of lightness and chroma. This formula can detect perceptible color differences.

• dE CMC 2:1

  Lightness has twice the weighting of chroma. This formula can detect acceptable color differences.