1. A system for brightness-sensitive automatic white balancing of an electronic color image captured by an electronic camera, comprising: a processor; and a memory including: a plurality of brightness-specific color-weighting maps each specifying illuminant-specific auto white balance parameters, a plurality of brightness range definitions respectively indicating applicability range of the plurality of brightness-specific color-weighting maps, and machine-readable white balance instructions, encoded in a non-transitory portion of the memory, that, upon execution by the processor, white balances the electronic color image, the white balance instructions including brightness instructions that, upon execution by the processor, determine brightness of a scene represented by the electronic color image and select one of the plurality of brightness-specific color-weighting maps based upon the plurality of brightness range definitions, each of the plurality of brightness-specific color-weighting maps being a probability distribution of an ordered pair of color ratios, the ordered pair of color ratios defining the auto white balance parameters, the probability distribution composed of a plurality of illuminant-specific probability distributions each associated with a different spectral type of illuminant.