[argyllcms] Re: RGB printer profiling, A2B tables

  • From: Klaus Karcher <lists@xxxxxxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Fri, 12 Jan 2007 11:57:06 +0100

Graeme Gill wrote:
I certainly don't know what they are doing or the purpose of such
mappings in the A2B tables when applied to ICCV2 files. I can
imagine using such an approach to improve perceptual rendering
intechanegebility amongst profiles all generated by the same package,
but it may actually work against intechanegebility with profiles
from other packages.

AFAIK that's what Heidelberg advertises as "Inverse [sic] Gamut Mapping".

In my humble comprehesion, the PRMG (http://www.color.org/ICCSpecRevision_22_02_05_PRMG.pdf) is (or shoud be?) a agreed-upon determination of the PCS gamut boundary and a perceptual gamut mapping should map the source gamut to the PRMG without clipping in a "pleasant" way (however defined). In addition, it needs a vendor independent, invertible gamut mapping algorithm to be of use. If the user wants clipping, he has to boost the chroma of the source image to exceed the PRMG limits. Did I miss or fail to see something?

Klaus

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