  We describe an affine transformation on the (CIE) color matching functions
and map the spectral locus as a circle. We then homogenize the right circular
cylinder erected by the circle, with respect to a normalizing plane and develop
an analytical equation to the chromaticity cone, for the spectral colors. In
the interior of the (CIE) chromaticity diagram, by homogenizing elliptic
cylinders with respect to the normalizing planes, analytical equations to
subsets (also cones) of the chromaticity cone are developed. These equations
provide an algebraic method for describing color perception. As an application
of the interior chromaticity cones, we demonstrate that by sectioning
homogenized cones with planes and projecting, analytical equations to the
Macadam ellipses may be derived. Further, the cone equations are used to
propose new types of color order systems.
