White & Colour Balancing

In white balancing, a sensor on the camera averages the light in the scene and automatically adjusts the camera's internal colour circuitry to zero out any generalised colour bias. Although this works reasonably well under the proper conditions, automatic circuitry can't be relied on to always produce accurate colour. So skilled camera operators adjust the white balance themselves. White card or paper is useful to test with. With the camera zoomed in full frame on a pure white card, the operator pushes a white balance button and the camera's chroma channels will automatically adjust to produce pure white. When the dominant light source in a scene changes in any way, you must again white balance your camera.

Going from sunlight to shadow will necessitate white balancing the camera again, as will moving from outside to inside. When shooting outside, even the passing of a few hours will result in a slight colour shift in illumination.

If you do not white or colour balance your camera, you risk scene-to-scene colour changes. This is especially noticeable with skin tones in multiple-camera productions.

 

Colour balancing is much like White balancing and is easy to to control, however can be difficult when using more than one camera for a scene. Some studio and field cameras are designed to use a "smart card." About the size of a credit card, it records all the parameters on the first camera you (carefully) set up. Then when you insert this card into successive cameras, they will adjust them to conform to the first camera's parameters. Studio engineers use a central camera control unit to adjust all studio cameras at a central location.

Colour reproduction is subjective since the human eye can be fooled quite easily to not be able to detect the colour variations between cameras. Studies have shown that people prefer the colours on their TV sets to be more saturated than in real life. This preference does not mean that the hues are inaccurate but the colours are more stronger to the human eye.