Hi, Thanks for reporting, I am bringing this issue to the ICC.
Regards Marti Quoting Esben Høgh-Rasmussen Myosotis <e...@phaseone.com>: > 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 > > > > > ------------------------------------------------------------------------------ > _______________________________________________ > Lcms-user mailing list > Lcms-user@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/lcms-user ------------------------------------------------------------------------------ _______________________________________________ Lcms-user mailing list Lcms-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/lcms-user
