Vision Response vs. Planck’s Black Body Curve
Color temperature is based upon the idea of a Planck black-body radiator.
Here’s a Tech Note that shows how our eyes respond to the Planck Black-Body radiator.
For a lamp filament at a certain ‘color temperature’ there’s a curve of how our eyes respond to the lamp. Pete put this into a MathCAD model, and there’s a pdf here that shows off a few nice graphs.