Hunter Lab

It is another colour space that is referred to as Lab, like CIELAB (\(L^*a^*b^*\)).
It was also derived from CIE 1931 XYZ Colour Space.

L is a correlate of lightness and is computed from the Y Tristimulus value using Priest's approximation to Munsell value:
\(L=100\sqrt{\frac{Y}{Y_n}}\), \(Y_n\) is the Y tristimulus value of a specified white object.
a and b are termed opponent colour axes.

CIELAB has almost entirely replaced Hunter Lab.