CIELCh
CIELCH is a cylindrical representation of the CIELAB and CIELUV color spaces, designed to describe color using lightness, chroma, and hue. It provides an intuitive way to think about color: L* denotes lightness, C* denotes chroma (color intensity), and h° denotes hue angle around a color wheel. There are two common variants: CIELCHab, derived from CIELAB, and CIELCHuv (often referred to as CIELCHuv), derived from CIELUV.
In the CIELAB-based form, chroma is C* = sqrt(a*^2 + b*^2) and hue is h° = atan2(b*, a*) in
Advantages of CIELCH include a more perceptually uniform separation of lightness, chroma, and hue in many regions