Me and my consumer camcorder are always in a situation of mixed lighting. I shoot my daughter in her classroom with light from the window and fluorescent lights, some friends in a house with mixed fluorescent and incandescents, etc. what will I do to get a perfect white balance in these situations? Thanks.
Keep the windows behind you, for one thing. If you balance for daylight, tungsten sources will be red or ruddy, but this "warm" look is more pleasurable than nalancing for tungsten where there's a lot of blue daylight coming in and making people look pale and sickly. And flourescent makes everybody look green. The compromise is to balance to the dominant light in the shot, whatever that is, and make the best of the off-color sources by shooting around them. Sometimes you can override a blue or green room if you bounce a big enough halogen light off the ceiling or a big white wall nearby. But in many situations you may not be able to do that. Some folks like to use a white card to fool the camea by reflecting part of the daylight and part of the incadescent. This works sometimes but I don't do it too often.
I continue to be astounded by the improvements in "shockless" automatically-adjusting white balance in modern cameras, but they do best when presented with one choice of temp at a time, so don't put the windows and the practicals in the same shot and you will do better.