Even the best digital cameras struggle with consistently reproducing accurate color. Images shot with incorrect white balance may have unnatural looking red, yellow or blue tints that can be time consuming and difficult to correct.
To help photographers cope with this problem, digital camera manufacturers have designed their cameras with multiple white balance functions, including Custom White Balance, Automatic White Balance (AWB), and factory Preset color temperature settings for Sun, Shade, Tungsten, Fluorescent, Flash, and Cloudy. When shooting, photographers must select one of the camera's white balance settings to apply in-camera, or photograph a neutral reference tool to apply later in post processing if using the RAW file format.
Unfortunately, Auto White Balance (AWB) often produces maddeningly inconsistent color results, and the color temperatures assigned to the camera's Preset white balance settings often do not reflect real world lighting conditions, causing a color-cast.
Using the Custom White Balance function remains the most reliable way to consistently reproduce accurate, balanced color in digital cameras. The custom white balance function eliminates the inconsistencies of AWB and the gross generality of factory Preset color temperatures because it allows the user to calibrate the camera to an exact color temperature at image capture. The custom white balance procedure requires a neutral reference like the ExpoDisc to measure the color of light accurately.