>>> My question is, how can I "instruct" lcms to use the B2Ax tables instead? > > This is a feature I miss in LCMS too - as well as a way to tell the > transform not to use any LUTs at all.
Would be nice, but unfortunately it goes against the spec, please see ICC.1:2004-10: "8.10 Priority of tag usage There are several methods of colour rendering that can function within a single CMM. If data for more than one method are included in the same profile, the following selection algorithm shall be used by the software implementation. For input, display, output, or colour space profile types, the priority of the tag usage for each rendering intent shall be: 1.BToA0Tag, BToA1Tag, BToA2Tag, AToB0Tag, AToB1Tag, or AToB2Tag designated for the rendering intent 2.BToA0Tag or AToB0Tag 3.TRCs (redTRCTag, greenTRCTag, blueTRCTag, or grayTRCTag) and colorants (redMatrixColumnTag, greenMatrixColumnTag, blueMatrixColumnTag) The available valid tag with the lowest priority number defines the transform." That means that any CMM bypassing this priority is misunderstanding the profile and using it in a way it was never designed to work. I have seen some CMM claiming to do color management and then only using shaper and matrix on CLUT-based profiles. This is clearly wrong and in the best case it may result in mixed intents. Note that a profile creator may choose to use the matrix-shaper for other functionality, for example a profile having matrix-shaper and AtoB0, when properly handled will use the AToB tag for device to PCS and the inverse of matrix for PCS to device. That does not mean a CMM could safely use the matrix for device to PCS. Anyway the topic is interesting enough. Regards Marti > So more control flags would be nice. (At the moment I'm creating a > profile copy and deleting the LUT tags....) > ------------------------------------------------------------------------------ _______________________________________________ Lcms-user mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/lcms-user
