Gerhard Fuernkranz wrote: ... >> For input profiles, the ICC spec does not requre the presence of B2A >> tables, since it is not assumed that a scanner profile is ever used >> for PCS -> device transformations. But LUT-based display and output >> profiles should contain both, A2B and B2A tables. If they don't, then >> they actually do not comply with the ICC spec. Of course, if a >> display or output profile is only > ... used for PCS -> device transformations, then the A2B tables won't > be used.
A2B1 is used for soft proofing, or am I mistaken? >>> Is this a generally unsolved problem, or do proprietary solutions >>> exist? >>> >> I fully agree with Marti, that this is not an easy task. But >> basically, any profiler must somehow solve this kind of problem. If >> you want to look at an example, see http://www.argyllcms.com/ Thanks, Gerhard. I did look at the fixrev program, if that's the one you mean. If you don't mind my saying so, very elegant. I don't understand the details, but the problem is evidently more complex than simply populating the inverted LUT with N dimensional interpolated values from the LUT you are inverting. Not that that isn't complex enough :-) For my current application, which involves applying user specified curves to a profile, I've gone the route of adding my transforms onto the (hopefully correct) end of the existing AtoB and BtoA tables or TRC curves as necessary. I had thought I could take a shortcut, and avoid cumulative error, by doing only one LUT and inverting to get the other. Mike Russell www.curvemeister.com www.geigy.2y.net ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ Lcms-user mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/lcms-user
