David Briggs teaches at the Julian Ashton Art School in Sydney Australia. He has put together an amazing site that helps painters and digital artists understand color in a very technical and thorough way. I've read through most of his stuff and if you are a student of color I encourage you to do so as well.
His explanations are very technical. I find them fascinating.
Figure 10.1. Colour relationships for a red ball on a white table. Specular reflection on tabletop and sphere both move along lines of uniform saturation between light and dark (Principle 1). Dotted lines shows table and ball maintaining the same ratio of relative brightness in light and shadow (Principle 2). Sphere painted in Photoshop CS2.
Figure 7.4 Hand-painted colour circles from the 1708 edition of Traite de la Peinture in Mignature, attributed to Claude Boutet, including the oldest example of the symmetrical 12-hue artists colour wheel (right). Picture Credit: Kuehni (2003)