You need to adjust the white balance on your camera before filming. Why?
Because camera, unlike your eyes, need to be told what is white. What you see as white in real life needs to be translated to the camera, so it can adjust itself. When doing white balance in your camera setting, you are telling the camera which color temperature is going to be set as white.
Color temperature is measured in Kelvin (K).
2000 Kelvin; Candle light setup
2800 Kelvin; Normal tungsten light
3400 Kelvin; Normal tungsten light
4500 Kelvin; Fluorescent light, hospital and office light.
5600 Kelvin; Sun or day light
6500 Kelvin; Sun or day light
8000 Kelvin; Moon light color, very blue on the subject
Orange lights are called Tungsten (Around 3200 K). Day lights are around 7000 K and they look blue. Orange lights are “warm” and Blue lights are “cool”. If you color balance on 2000 Kelvin, you are telling that 2000 Kelvin is white. Therefore if there are other light sources that have higher color temperature, it will look very blue. E.g. the sun light will look very blue in this case.
On the other hand, if you set the white balance on 8000 Kelvin, i.e. you tell the camera that the moon light is white. Then any color temperature that is lower, the image will look orange.
You generally do not want to mix different types of color temperatures. The image looks conflicting. But normally, most situations have mixed lights, such as sun light (5600 K) from outside pouring into a house lit with 3400 Kelvin light.
This is where gels come handy. You can use gels to change either the sun light color temperature or the room light temperature. One way is to put gels on windows to bring down the color temperature to match the house light. Or you can add gels on the indoor lights to match the outdoor light. Now that you have a matching color temperature, your image will have a nice symphony of balanced color temperature.
Common Gels are;
CTO Gels – Orange gels that converts daylight (5600K) to tungsten (3200K)
CTB Gels – A blue gels that coverts tungsten light (3200K) to daylight.
CTO; Color temperature Orange
I am a documentary/News cameraman based in London.