Getting color temperature dialed into your camera correctly serves many purposes. Whether its getting the skin tones of your subject accurate or using as it as a creative tool to advance the narrative through the use of color, knowing how you can use mixed lighting sources to your advantage can help you when your in a pinch, or offer you more creative options when lighting a scene.
Mixed Lighting can be a Nightmare
When I first started as a DP (Director of Photography) I would always try to get my white balance unified in the scene, which meant when I arrived at a location with a ton of natural light I had a uphill battle.
Daylight is at 5500K whereas my ARRI Tungsten Fresnel lights are all emitting light at 3200K (Tungsten). If you try and white balance the mixture of color you end up with something that just doesn’t look right.
To correct this I would throw full CTB (Color Temperature Blue) gels on the lights to bring them closer to 5500K, meanwhile losing a stop of light for every full CTB. At the time I had a modest amount of power in my location kit, so I needed every bit of light I could get and the CTB gels were robbing me of my light!
The other solution was to black out the windows and try and rebuild the light to my liking but this limited the parts of the scene I could use as the background as well as requires more light power overall.
Thankfully someone taught me to work with the mixture of color temperature and use it to my advantage, instead of pulling my hair out trying to to fight it.
STEP 1: Light your scene as you normally would, using the tungsten lights to illuminate only foreground objects, such as your talent.
STEP 2: Use a portion of the scene that is lit by daylight as the background, such as a window or section of the room with daylight spill.
STEP 3: Now set the color balance your camera to 3200K (Tungsten) and watch the magic happen!
What you should see happen is the foreground will look neutral and the background will go a nice cool blue.