The color an object appears can be set using a Black Body node, which accurately simulates the color an object should have. This is however relative to the color balance/white balance used. An object will appear blue if it's "temperature" is 6000K if the image is balanced at 4500K (and 4500K appears white); If, however, it's balanced at 8000K, the same object will appear yellow/red.
Is there a way to adjust the color balance temperature?