I'm sorry, playing with color conversions until late does bad jokes sometimes :) --cat is obviously not needed, because argyll already knows the reference white (illuminant.sp) and the PCS white (D50 for prophoto.icm). So the command will be: spec2cie -i my_custom_[A|D50|D65]_illuminant.sp -o 1931_2 -n --rgb Prophoto.icm colorchecker.ti3 copypasteme.ti3 Anyway, having an option to save chromatic adapted XYZ/Lab values can still be useful for other purposes. Darkbasic Il 09/11/2010 01:04, Niccolò Belli ha scritto: > Hi, I'm writing because it's actually quite hard to do it with Argyll > and I have a wishlist for spec2cie. > Tindemans ACR calibrator script > (http://www.21stcenturyshoebox.com/downloads/ACR-Calibrator-L-v31.jsx) > stores the ColorChecker reference values in ProphotoRGB. It stores > values for three illuminants: A, D50, D65. > If you convert spectral readings w/ spec2cie > spec2cie -i illuminant.sp -o 1931_2 -n measurement.ti3 converted.ti3 > then you have to do CAT from the source illuminant (illuminant.sp) to > the destination illuminants (A, D50, D65) and also convert the XYZ/Lab > values to ProphotoRGB. > This is a *VERY* long work to do manually with the help of the Bruce > calculator (http://www.brucelindbloom.com/). Also, the Bruce calculator > only supports few illuminants, so you have to implement your own CAT > into an excel sheet if you want to use your custom illuminant. > > So I suggest to add two more parameters to spec2cie: --cat and --rgb > The first will do chromatic adaptation transform to the given > illuminant, the second will convert the chromatic adapted values to the > selected profile. > > So the command will be: > spec2cie -i myilluminant.sp -o 1931_2 -n --cat [A|D50|D65] --rgb > Prophoto.icm colorchecker.ti3 copypasteme.ti3 > > Cheers, > Darkbasic