Although our eye will automatically adjust to different light sources, the camera needs to be told which is which. Many cameras have automatic white balance functions but the surest way to know is to explicitly tell the camera. This is done by holding a white card or piece of paper in front of the lens and indicating to the camera that it is looking at white, commonly done by pressing a button on the body of the camera or in a menu setting labeled “White Balance”. With white established as a reference point, the camera can correctly interpret the color temperature of the light and calibrate itself.
Improperly balanced footage is easy to identify. Shots in which everything appears blue in the camera original are ones that was balanced for artificial lighting but shot in daylight. Shots that appear orange are ones that were balanced for daylight but shot in a setting with tungsten or incandescent lighting. Regardless, you do not want an undesirable color shift. Check your white balance each time the lighting changes in a scene to ensure consistency in the color. The color of the shots can always be modified in post but it is wiser to maintain consistency in production.
For some projects, it can be desirable to intentionally shift the color temperature. “Cooling down” a shot means taking it in the direction of blue. “Warming up” a shot means taking in the direction of orange. This is a subjective choice but it is possible to use White Balance to change the color intensities captured in the camera original. This can be done on many cameras by manually taking control of the White Balance settings and shifting the temperature in one direction or another.
It is also possible to “trick” the camera into thinking a color is white. You can place a light blue card in front of the camera and explicitly tell the camera that it is white. Then you will “warm up” your shot and make all colors shift to orange. Conversely, you can take a light orange card and white balance to it and “cool down” your shot.