dt-l...@stefan-klinger.de :
Matthieu Moy (2019-Jan-24, excerpt):
dt runs
the image through the whole pipeline, displays the result and uses
it for the picker and histogram. A more rigorous approach would run
the image through the pipeline up to the output color profile, and
then export to monitor space to display the image and to another
monitor-independant space for the picker and histogram. That may
happen one day, but it's not how it is today indeed.
Hmmm, does that mean that the histogram is calculated from the
on-screen representation instead of from the image that would be
created just before export? I was hoping for the latter, and expected
that to be also used to implement gamut checking?
That comment ties is with what I am trying to do. Say I find that a
given matte paper shows detail between rgb(30,30,30) and (250,250,250)
(hypothetical for a b&w image), I would like to process the image so
that its tones fall appropriately between those values.
If the global color picker only shows values after conversion to the
monitor profile, then those values are not related to the values in the
image on export and cannot be used. I cannot know which areas of the
image fall below, at or above a precise threshold. Pressing the
softproofing icon does not help because although it does show the effect
of the printer profile visually, the values reported by the global
picker are the same as without softproofing, i.e. they reflect the
monitor profile and not the printer profile.
I've looked at the histogram with different monitor profile (without
checking the box in the global picker that affects the histograms), and
it does change, so it seems to work like the global picker. If that is
so (I would like a confirmation) then the situation is much worse
because even the histogram cannot be trusted when one wants to print.
I wonder if someone who knows DT better than I do could perhaps confirm
or deny these findings?
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