Lch is similar to it's cousin Cie-L*ab, except that it's been rearranged in the shape of a sphere which makes it useful for applications like high-end photo editing and retouching images. Read more about it here
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.
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Color conversions performed using the open source ColorMine library.