Sunday, October 21, 2012

How White Balance Establishes Color Temperature

When you take a photograph with a digital camera, the color temperature of the scene is not taken into account until the image is processed by the camera’s processor. The camera refers to its white balance setting when it processes the image.
When the camera’s white balance is set to auto, the camera assumes the brightest value is white and adjusts all other colors in the image accordingly. If the brightest value is white, the colors in the image are rendered correctly. If the brightest color is yellow, the camera still assumes that value is white, and shifts all the colors out of balance. However, you can adjust the color temperature of a digital image. White balance is a mathematical process that calculates an image’s color temperature and applies the effects to the color values in the image after the RAW image is stored. That color temperature data is stored as metadata in the image. The digital data that makes up the original RAW file is unchanged. So, no matter what white balance or color temperature setting was applied at the time the image was shot, the color temperature of the image can always be corrected after the fact. Digital cameras’ RAW files solved the problem of color temperature flexibility that the chemistry of film never could.

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