Hsl is a cylindrical-coordinate representation of the Rgb color model. This representation rearranges the colors in an attempt to be more intuitive and perceptually relevant than the typical Rgb representation. It's frequently used for computer graphics applications like color pickers and image analysis.
Cie-L*ab is defined by lightness and the color-opponent dimensions a and b, which are based on the compressed Xyz color space coordinates. Lab is particularly notable for it's use in delta-e calculations. Read more about it here.
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Color conversions performed using the open source ColorMine library.