1. A process for a captured image, the captured image being a color digital image having an associated illuminant of unknown color, the process comprising the steps of: forming an image vector based on chromaticities associated with the captured image; applying the image vector to a correlation matrix to form a resulting vector, the correlation matrix having a first dimension corresponding to a set of candidate illuminants and having a second dimension corresponding to chromaticities; and based on the resulting vector, selecting at least one candidate illuminant from the set of candidate illuminants to be the associated illuminant of unknown color.