Hi Gerhard, >> You can also argue that some devices may have white >> point not at (255,255,255) or (0,0,0,0) > >Actually this is the _only_ issue I was really objecting. > >IMO the ICC spec does not strictly require a media WP located at >(255,255,255) or (0,0,0,0), but the WP can be located at nearly any >arbitrary color.
Ok, so then let's assume a RGB profile has the white point located at, say (200, 200, 200). In such case, the fixup would add an extra white-to-white at (255, 255, 255) but the previous (200, 200, 200) would remain untouched, so still mapping to white. Then comes the question... what about the zone between (200, 200, 200) and (255, 255, 255)? A well behaved profile would have all that zone mapped to white. Else, since the (200, 200, 200) is mapped to white, we end with a non-monotonic profile, that is, increasing device contone value would results in decreasing L* Ouch! that would mess up things to such extent I doubt an extra 255->white would make things worse. My point is, forcing this mapping is not destructive in any situation but the weirdest, non-monotonic, already faulty profiles. Please note that on "correct" profiles it has no effect at all. Also, I'm a bit concerned about adding extra code to check whatever the profile is broken. It can be done, of course. May be as easy as using the AToB direction to check if maximum contone maps to Lab (100, 0, 0) But more code means more chances of bugs, and it seems to me there is no real need to do so. >- Btw, what about icclink? > Is the remapping also performed by icclink? > Is it possible to turn it off for icclink as well? icclink currently always fixes white to white. There is no way to turn off that feature. >- And what about icc2ps? > It might also be desirable to create CRDs which > eliminate scum dots. It is, indeed. PostScript code also eliminates scum dot, but in a different and more agressive way. It does local adjusts to map a,b=0 in the near nodes to white. The problem is again the encoding of a, b, which makes impossible to map white on an exact node. Since the device link is built by the PS interpreter, I had no other way to do that. And I have to use Lab in order to get some precission... Regards, Martí. ------------------------------------------------------- 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://productguide.itmanagersjournal.com/ _______________________________________________ Lcms-user mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/lcms-user
