I just released version 1.0.0 of colorspacious, a library for converting between colorspaces in Python, and thought that scikit-image might be interested. This is the library that we used to design viridis and several other new colormaps, and it includes common well-known colorspaces (sRGB, LAB, XYZ, xyY) along with several more sophisticated models for estimating perceptual correlates (CIECAM02), estimating perceptual similarity (CAM02-UCS), and simulating colorblindness, all wrapped up in a very easy-to-use interface. (There's basically just one function.)
Notable features of this release include a fancy new tutorial and reference manual: https://colorspacious.readthedocs.org/ and 100% test coverage.
Share and enjoy! -n