Hello there.
I am looking into the pit known as chromatic adaptation and noticed something
strange.
In the ICC specification, Bradford adaptation is based on the following
XYZ/cone-space conversion matrix:
[ 0.8951, 0.2664, -0.1614 ]
[ -0.7502, 1.7135, 0.0367 ]
[ 0.0389, -0.0685, 1.0296 ]
This is also what LCMS use.
This method is, presumably, taken from K.M.Lam's thesis "Metamerism and Colour
Constancy" (what he calls KING1 method I think). However, when I look in the
thesis, it specifies the following matrix:
[ 0.8951, 0.2664, -0.1614 ]
[ -0.7502, 1.7135, 0.0367 ]
[ 0.0389, 0.0685, 1.0296 ]
The numbers are the same, but the sign in A(3,2) is positive instead of
negative. The matrix is written in the same way 3 times in the thesis (unless
the OCR missed something; I did not actually go through all 426 pages).
Any ideas why there is this discrepancy? Are we using a buggy method for
adaptation due to a typo?
Esben H-R Myosotis
Software Engineer
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