Andy Ciddor of Video and Filmmaker writes a detailed and very technical article on understanding color temperature.
He writes, "Why does the color of light get cooler as the color temperature increases? If Lee 201 Full CT Blue converts 3200K tungsten light to 5700K daylight, why do two layers of 201 (or one layer of Lee 200 Double CT Blue) convert the same 3200K light to 26,000K? Is it actually possible to predict the outcome of combining correction filters? Color Temperature describes the colour (but not the brightness) of a light source by comparing it with the colors of light emitted by a standard object at a known temperature."
Read the full story here.