CIE L a b*
CIELAB is the most complete color model used conventionally to describe all the colors visible to the human eye.
It was developed for this specific purpose by the International Commission on Illumination
The * after L, a and b are part of the full name, since they represent L , a and b*, derived from L, a and b. CIELAB is an Adams Chromatic Value Space.
The three parameters in the model represent the lightness of the color (L , L =0 yields black and L=100 indicates white), its position between magenta and green (a, negative values indicate green while positive values indicate magenta) and its position between yellow and blue (b*, negative values indicate blue and positive values indicate yellow).