One challenge with indoor photography is shooting under mixed lighting conditions. The camera, whether digital or film, tends to pick up color variations in light sources with a much more dramatic effect than is noticeable with the human eye. If there is just one light source, the photo can be white balanced to correct for any color cast. However, if there are multiple light sources, the photo can only be balanced for one type, and parts of the photo acquire a strong color cast.
In this example, The subjects were front lit with a tungsten balanced strobe, but top lit with very green mercury vapor lamps. Photoshops replace color command under the image/adjustments menu does a fine job at shifting the hue of just one color in a photo.
Note the green cast in the hair on the before photo at left.
