Re: Media Testing for maclife.de
Re: Media Testing for maclife.de
- Subject: Re: Media Testing for maclife.de
- From: Uli Zappe <email@hidden>
- Date: Sat, 13 Sep 2008 05:01:26 +0200
Am 13.09.2008 um 02:10 schrieb Chris Cox:
Profiles are never used for calibration, but for profiling.
Then you don't understand how all of the software works.
It seems to me that it's rather a case of misusing well established
concepts. As somebody else already pointed out, it was probably not a
good idea by Adobe (or whoever else did that) to call their (as you
call it) "characterization" code "profiles", but they did - and now
there seems to be confusion about the use of the word "profile". I use
it in the sense of "ICC profile", you obviously don't.
(some attempt to use ICC profiles for part of their calibration)
Can you provide an example? (That would make clearer what you mean.)
Would Capture One PRO, which uses ICC profiles for the camera-specific
color mapping, be an example of what you refer to? If so, that's *not*
(part of) calibration, that's profiling. Calibration is *not* about
"translating" device specific data, but rather about putting them into
a stable, well-defined state. The "translation" part is done by
profiling afterwards.
Calibration is the process you'll have to perform before profiling,
be it a monitor, printer, scanner or - a camera. For the camera,
this process is or at least includes setting the white balance.
This part might be a language issue - but it is important, and
something that you are apparently misunderstanding.
It's the standard definition, just again reconfirmed here on the list,
and the definition found in standard literature about color management.
Characterization for a digital camera can generally be encapsulated
into an profile (relating sensor values to CIE colorimetry). The
format of that data does not matter.
OK.
But white balance is not directly part of the characterization
because it is very illumination dependent (not static from image to
image). How to achieve white balance under multiple lighting
conditions should be part of the characterization. But that part
cannot be encoded into a standard ICC profile.
Of course not. Hence the difference between calibration and profiling
(only to be performed *after* calibration).
This problem has led some software makers to add other calculations
outside of the ICC profiles they use to hold characterization data.
In case Capture One PRO is an example for such a software maker (see
above), then yes, you could describe it that way, but that would be
very unconventional. The way Phase One themselves describe it (and I
would describe it), is that they calibrate the camera first (including
white balancing, which is - correctly, from my POV - performed before
assigning the ICC profile), and then (after calibration) assign an ICC
profile that describes this still camera-specific color space the data
is still in, thereby enabling the CMM to convert it into a standard
color space. The term "characterization" isn't used at all.
This is indeed the optimal workflow for custom-built ICC camere
profiles, which can thusly replace the Capture One camera default ICC
profile.
Calibration would bring the data from the device into a standard
No, that's the task for the profile (or at least, should be in a clean
workflow).
What you are attempting to test is the artistic part - after the
calibration has been achieved, after the white balance has been
performed.
What you call "artistic part" for whatever reason is simply the
canonical profiling procedure, be it for monitors, printers, scanners
or cameras. I have no idea what should be "artistic" about that; it's
all about colorimetry. Every single software vendor that offers ICC
camera profiling software calls what you call "artistic rendering"
simply "camera profiling". Go figure.
Even if you are trying to achieve colorimetric results, you are
attempting to apply a rendering via ICC profiles AFTER the
calibration rendering has been done.
Of course. That's the standard workflow for ICC profiling.
But you have to be very careful in the tests to know when the
profile data is applied, and something about how the calibration
rendering is applied.
In a professional software with a correct workflow, such as Capture
One PRO, the ICC profile is assigned after setting the white balance,
but before any color manipulation tools.
You cannot reasonably compare profiles for artistic rendering to
profiles used for calibration/characterization.
But that is what you tried to do.
No, what I tried to compare is the capability of different software
solutions to provide metrologically correct color reproduction in
photos. From the perspective of a potential user (and my review was
written for those, and with this perspective), it doesn't matter at
all *why and by which means* a software solution achieves or fails to
achieve the goal of metrologically correct color reproduction; the
only question is whether it achieves it.
One of your mistakes is that you didn't understand exactly what you
were testing (see above).
It rather seems to me that you don't understand what I wanted to test.
First, learn what is going on as much as you can, then ask
questions, then get reviews from people who know the topic well, ask
more questions of those people, make corrections, get them to review
again - when they approve, then publish.
(more or less like a thesis)
How would you know that I didn't "get reviews from people who know the
topic well"?
What would happen if you submitted a thesis to a university that
contained obvious mistakes and unsupported conclusions? Your
advisor or the reviewers would tell you that you had mistakes and
that your conclusions were unsupported and to please go work on it
some more. Very much like I'm doing here.
Yeah, that pretty much sums it up: you are the professor, and I am the
student. It's simply unconceivable it could be the other way round,
isn't it?
If I were you, I would have removed the original review
Even you could not remove a review that had run thru the printing press.
and put an apology in it's place long ago.
Apology?!?! To whom? For what?
The translation should wait until you fix the problems in the
original review.
Problem is, I don't see any problems, nor does anyone who read the
review. So it seems I'd need your wisdom to even see the problem, but
you cannot read my review until it's translated. Catch 22.
One question: since you're so convinced that my review is sub-par
(although you can't read it), can you offer any possible explanation
for the fact that I received several unsolicited congratulations for
the quality of my review from people throughout the German-speaking
industry?
Certainly you should withhold reviews of the DNG profile technology
and results until you understand what they are doing and what they
are for.
Why isn't it a legitimate viewpoint to just look if they can help
Lightroom to improve metrologically correct color reproduction, or
can't?
True, but the logically only alternative to the intent to deliver
optimal profiles is to intentionally deliver suboptimal profiles. I
don't say such a behavior is impossible, but users would certainly
want to stay away from the products of such a company.
Again, you have problems with your logic.
Other possibly hypotheses: they default to a pleasing rendering,
That's identical to intentionally delivering suboptimal profiles. Keep
in mind I were *not* speaking about profiles in general but about
those generated by the DNG Profile Editor via the means of measuring
the ColorChecker 24 chart. By employing measurements, a software makes
implicitly clear that measurements set the standard for its procedure.
Providing a voltmeter that does not display the measured voltage but
funny and pleasingly looking combinations of numbers would be too
irrational to assume. Whoever offers a software that includes
measurements agrees implicitly to be evaluated metrologically.
In the end, all of this doesn't matter. If a user wants metrologically
correct images from his camera and finds Lightroom can't deliver (at
least not without expensive tweaking), it's simply not the right
software for him. It does not matter in this context if Adobe was
unable or unwilling to provide (metrologically) better quality.
??? What accusation?
Please re-read what you have written.
It might be just a translation issue, but many of your claims are
more forceful than expected in a review.
It seems to me the more forceful statements were coming from your side.
I'm really really tired of all this. I was asked by several readers of
this list to provide a translation of the review. Although I hardly
can afford the time necessary to do this, I agreed in order to do the
English speaking community a favor, and now I find myself being
constantly attacked for this by one individual who is convinced the
review is so bad it should not even be translated, although he himself
cannot read it.
In any case, with all this arguing, I wasn't able to finish the
English review until now, and now I cannot do anything during the next
2-3 weeks minimum. I will reconsider the whole situation then.
Bye
Uli
________________________________________________________
Uli Zappe, Solmsstraße 5, D-65189 Wiesbaden, Germany
http://www.ritual.org
Fon: +49-700-ULIZAPPE
Fax: +49-700-ZAPPEFAX
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