[argyllcms] Re: Profiling between two images

  • From: Pascal de Bruijn <pmjdebruijn@xxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Tue, 3 Feb 2009 18:03:14 +0100

On Tue, Feb 3, 2009 at 2:26 PM, Gerhard Fuernkranz <nospam456@xxxxxx> wrote:
> Pascal de Bruijn wrote:
>> I understand, however, when I use -qu instead of -qh/-qm/-ql for some 
>> targets,
>> the curve is totally different. And when comparing to the source image the
>> curve in the -qu generated profile seems to fit better.
>> I'll do some more experimenting first, and possibly provide a sample
>> this evening.
> The smoothest one would be a matrix/gamma (-aG). But without looking
> thoroughly at the actual data, I don't feel able to asses whether the
> transformation done by the camera can be modelled by a matrix/gamma or
> matrix/shaper reasonably well, or whether even a 3D LUT would be
> required. It's certainly a trade-off eventually - you need to try.

The gamma doesn't cut it... The shaper is a quite important part of the profiles
in question.

I never expected exact results, with regards to my camera (or DPP) processing.

I have attached a .ti3 file, which gives completely different shaper
when executed

  colprof -qu -aS

Than when it's executed like:

  colprof -qh -aS
  colprof -qm -aS
  colprof -ql -aS

In all four cases the matrix seems nearly identical.

The odd things is that the qu shaper, seems better matched when applying it
to image data (when comparing it to the original image data).

So that's why I was wondering whether it would be possible to smooth the qu

And of course I just think it's odd that quality settings have such a extreme
effect on the total shape of a shaper.

Pascal de Bruijn

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