Color is an important and useful feature for object tracking and recognition in computer vision. However, it has the difficulty that the color of the object changes if the illuminants color changes. But under known illuminant color it becomes a robust feature. There are more and more computer vision applications tracking humans, for example in interfaces for human computer interaction or automatic cameramen, where skin color is an often-used feature. Hence, it would be of significant importance to know the illuminant color in such applications.This paper proposes a novel method to estimate the current illuminant color from skin color observations. The method is based on a physical model of reflections, the assumption that illuminant colors are located close to the Planckian locus, and the knowledge about the camera parameters. The method is empirically tested using real images. The average estimation error of the correlated color temperature is as small as 180K. Applications are for example in color based tracking to adapt to changes in lighting and in visualization to re-render image colors to their appearance under canonical viewing conditions.