[argyllcms] Re: Qs re: mapping of Scanner Input Profiles

  • From: Graeme Gill <graeme@xxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Wed, 28 Jan 2015 14:06:21 +1100

Derin Korman wrote:

> Graeme, you had mentioned that Matrix profiles are only colorimetric, which
> is what I had assumed, but then suggested that using perceptual for
> scanners is a good idea. Did you mean that I for cLUT based profiles?
> Shaper can't do this either right?

Sorry, I've lost the context of this conversation.

Doing gamut mapping with input profiles isn't a typically useful workflow
 - generally you want to capture an image as faithfully as possible, and
then manipulate it in the process of adding a creative interpretation,
or in converting it to a generic or specific output medium.

Gamut mapping is typically useful in device links or the B2A tables of
device profiles.

> Following that question, If I know what my working space profile will be in
> the end, is there a way to build a profile that has a specific a2b table to
> optimize the transformation? ie. going from scanner profile > adobe rgb

See above. It's not a workflow I would recommend, nor is it supported
by Argyll. There are a couple of options in dealing with absolute vs.
relative white point handling of input profiles, but that's about it.
The main aim is to interpret the device dependent values as colors,
and then go from there.

> finally, and on an unrelated topic, is there a way to output a diagnostic
> that would show which patches show what sort of error like some other
> software does? This is very helpful in figuring out when something
> unexpected goes wrong with a patch or two.

Assuming you are referring to the profile creation step rather than
scanin, then yes - use profcheck. See

Graeme Gill.

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