Editing Color balance (section)

===General illuminant adaptation===
The best color matrix for adapting to a change in illuminant is not necessarily a diagonal matrix in a fixed color space.  It has long been known that if the space of illuminants can be described as a linear model with ''N'' basis terms, the proper color transformation will be the weighted sum of ''N'' fixed linear transformations, not necessarily consistently diagonalizable.<ref>{{Cite book | author1 = Laurence T. Maloney | author2 = Brain A. Wandell | chapter = Color constancy: a method for recovering surface spectral reflectance | title = Readings in Computer Vision | editor1 = Martin A. Fischler | editor2 = Oscar Firschein | year = 1987 | publisher = Morgan-Kaufmann | isbn = 978-0-934613-33-0 | chapter-url = https://books.google.com/books?id=W5hLHUI8U-kC&q=maloney+wandell&pg=PA293 | url = https://archive.org/details/readingsincomput00fisc }}</ref>