White Balance

A simple technique that attempts to balance the colors in a photograph, which may deviate from the perceived colors because of:

• The cast of an Illuminant
• Camera sensor sensitivity

If the white balance is ‘off’, all the colors in the image will be distorted. If you are using an app that determines the color of an object through your phone/camera, it is imperative to white balance so the app can determine the correct color. Before white balancing though, you must determine the deviation of the photo’s white from the Equal Energy White, by one of two means:

• Known ‍Illuminant – The photographer of an image can indicate the type of Illuminant that they are shooting under and therefore the general cast of the scene. An incandescent bulb will have a much warmer cast than the cool cast of a cloudy day.
• Content Aware – There is no knowledge of the Illuminant, but there are some reference objects in the frame that are known to be a neutral color (white or gray). This can be a specific White Reference like a sheet of paper or color chart, or something less precise but often available like teeth or eye white.

Once the deviation from the target White Point is known, the colors of the image can be uniformly shifted. The target white point is Equal Energy White if used for Color Identification, but white balance for aesthetics may use some other target white point like D65.