An HSV to RGB converter built for rainbow gradients.
With regular HSV, hue changes one value at a time. For example, as hue goes from 0° (red) to 60° (yellow) (with value and saturation unchanged), there are twice as many pixels lit. Think about that, only because a color is a different hue, it's twice as bright.
Using /visualization.py, here is a comparison of HSV.
HSV converted to RGB using a standard library: