HSL

From ColorWiki

HSL (also HSB: Hue, Saturation, Brightness) is a representation of color in the RGB colorspace.

HSL describes colors as points in a cylinder whose central axis ranges from black at the bottom to white at the top with neutral colors between them, where angle around the axis corresponds to “hue”, distance from the axis corresponds to “saturation”, and distance along the axis corresponds to “lightness."