[argyllcms] Calculate RAW importer profiles ?

  • From: Adriaan van Os <gpc@xxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Mon, 27 Jul 2015 09:41:54 +0200

My apologies if this has been discussed again. I searched for the word RAW in the archives but got quite a large number of hits.

A well known problem is that the output of RAW importers doesn't match the gamut of the camera JPG output. For example, when I import a Nikon .NEF with Nikon's proprietary Caputure NX 2 software, the produced TIFF matches the JPG exactly. When I import the same .NEF with (say) the OS X built-in CGImageSource RAW importer, the colors don't match. And I assume that importers like dcraw and ufraw have similar problems.

Assigning different profiles to the TIFF imported RAW after import gives different levels of deviation from the camera JPG. Of course, the problem is that camera manufacturers keep part of the RAW image data format secret. And maybe, the RAW importers should do a better job at color management.

But many cameras do have an option to output both RAW and JPG. And the JPG does reveal the secret of how the imported RAW should look like (for a specific set of camera settings). So, why not take the JPG and the RAW imported TIFFs, compare them and calculate a "raw importer" profile from both. That profile, when assigned to the RAW imported TIFF would then represent the best possible color match with the JPG (for a specific set of camera settings).

Would this be possible with argyll ? If so, it would offer users a quick way to create a "raw importer" profile from a (statistically relevant) set of RAW and JPG images. Or at least it would be better than the current (rather dissatisfactory) situation.


Adriaan van Os

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