[argyllcms] Re: Gamut mapping problems in 1.1.0

  • From: Klaus Karcher <lists@xxxxxxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Mon, 09 Nov 2009 01:42:53 +0100

Hi the other Martin ;-)

Martin Weberg wrote:
I did the following conversions. No tiffgamut used.

1. collink -G -ip -cmt -dpp ProPhoto.icm ISOcoated_v2_eci.icc devlink.icc
2. In Photoshop I converted Bill Atkinson's Lab Test Page to
ProPhotoRGB colour space.
3. Then, conversion cctiff -ip ProPhoto.icm -ip ISOcoated_v2_eci.icc
rgbinfile.tif cmykoutfile.tif
4. and cctiff devlink.icc rgbinfile.tif cmykoutfile.tif

The whole image from step 4 is really desaturated compared to 3.

That's consequential. In step 1 you create a gamut mapping that compresses the whole, huge ProPhoto space into ISOcoated_v2. In step 3 you use the precalculated gamut mapping of ISOcoated_v2 to compress a much smaller gamut (AFAIK something like the Pointer space) to ISOcoated_v2. Step 3 gives you more saturation, but clips everything outside the Pointer space.


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