White balance can be tricky. If your subject is backlit by daylight and frontlit by a lightbulb, you run the risk of a yellowish face and a bluish background. Save yourself with flash: Its color temperature will balance the backlight. No flash on hand? Shoot with RAW, process for each kind of light, then combine the different versions with image-editing software.
—From Photo Emergency by Debbie Grossman (March 2007)