Looks like a very useful little library. Although, have you looked at OpenColourIO and its Python bindings? It is the VFX industry standard for working with colour spaces, most companies will use OCIO for colour management throughout the process.
This looks really useful. I've played around with colormaps in a few visualization projects, but I've never made the time to learn about the various color packages.<p>What does this add to colormath and grapefruit?
Unrelated to the library itself: I dislike when python projects have an external website containing the docs, and have no docstrings in the code itself. Not only is the code harder to read, but it makes the inbuilt help() useless.
Doesn't seem terribly well specified. Is the rgb space actually sRGB? And what is the parameter to brighten/darken/saturate/desaturate?