DV Info Net - C100 and white balance

Seth nailed it - it's about skin tones. Add one additional consideration - artistic intent.

Consider a scene in a dark control room. The face is dimly lit by a bluish white light and is dominated by red lights from the control panel. In this case, I'd leave the fill slightly blue and let the red dominate.

Personally, I love mixed color temperatures. I generally put a 1/4 or 1/2 blue gel on my hair/back lights. I balance to the fill/key (tungsten) to let the blue accents come through. This gives the feeling of light from a window in a room even when there is no window visible in the scene.

For me, single color temp shoots with perfect white balance and relatively high exposure have a clean/pure corporate feel. One might choose a pure, single color temp, but be aware of the look that you are choosing.

I regularly shoot a corporate speaking event. The main room lighting is LED, which has a higher temp than tungsten. I use a couple of tungsten ellipsoid stage lights - one front right and the other rear left of the podium. (I don't balance them as they would lose too much light.) We color balance at 3100K, which is slightly on the high side of the tungsten key/fill. Is it perfect? No. But it's adequate as skin tones look natural. After shooting many of these events, this is our established look. Were I to change to single-temp lighting now, people would probably ask me why I messed up the color. :)

For narrative works, one can go far away from neutral. Put kickers behind a sofa. Gel them in blue/red/green/yellow/whatever. Use colored Christmas lights in the background. Have a candle and keep it yellow. Show a natural gas flame and keep it blue. Typically balance the main skin tones, but let it go green if illuminated by an emergency exit sign.

Of course the classic case is sunset. If you custom WB, it's just another scene. Set the WB to 6500K and the reds/oranges come through.

It's good to know the technicalities of perfect white balance but don't let it limit the art. :)