chicken-color
CHICKEN Scheme extension - a port of Aubrey Jaffer's SLIB color module
This is a module suitable for converting between color spaces which are designed around the human sense of vision instead of the peculiarities and limitations of display hardware. These are color spaces with names such as XYZ, Lab*, Luv*, LCh (if you are familiar with the HSV and HSL color spaces, you're close to the idea).
Quoting http://people.csail.mit.edu/jaffer/slib/Color.html#Color
_ _
( | ) The goals of this package are to provide methods to specify,
\|\| compute, and transform colors in a core set of additive color
spaces. The color spaces supported should be sufficient for
working with the color data encountered in practice and the
literature."