Re: Media Testing for maclife.de
Re: Media Testing for maclife.de
- Subject: Re: Media Testing for maclife.de
- From: Andrew Rodney <email@hidden>
- Date: Wed, 10 Sep 2008 09:04:21 -0600
On Sep 10, 2008, at 7:53 AM, MARK SEGAL wrote:
Then there are those applications of photography I mentioned
yesterday where perceptual colour accuracy really is the objective,
not "pleasing" colours. In these latter situations it is reasonable
to want a profiling solution "out-of-the-box" which comes as close
as possible to "accurate colour rendition", but how close is possible
Even the ICC has been clear that the terms are muddy here (I like the
fact you too haven't strayed close to the good old and simplistic
"accurate color" and placed perceptual in the sentence). For example,
on the ICC white paper area of the site, there's this paper (http://www.color.org/ICC_white_paper_17_ICC_profiles_with_camera_images.pdf
):
It is important to understand that, except for applications like
copying art and
product photography where the picture is supposed to exactly match
the original
captured, pictures usually don't match the scene from a color
measurement, or
even necessarily an appearance standpoint.
And
If one tries to create camera profiles for
such files by photographing a target, the results will generally be
sub-optimal
because the profile will in effect be trying to undo the color
rendering applied by
the camera to get back to the scene. There will almost always be
errors, in part
because of the limitations of reflection target based
characterization.
And
Also, ICC color management workflows generally assume that the
colorimetry
expressed in the PCS is of a [color-rendered] picture, and not of a
scene. There
is currently no mechanism to indicate that the colorimetry
represented in the PCS
by a camera profile is relative scene colorimetry.
The paper is careful in not over promising what some suggest a camera
profiles provides.
And then there's this paper which I worked on with Jack Holms of HP:
http://www.color.org/ICC_white_paper_20_Digital_photography_color_management_basics.pdf
It too attempts to provide a basis for what should be considered an
accurate capture versus a pleasing one.
The idea of taking output referred images and somehow pushing the
toothpaste back into the tube to produce a colorimetric match
numerically, then dismissing the initial Raw converter settings, and
further saying the numbers are solely the results of an input profile
is a stretch I'm not comfortable making. Others don't have any such
problem associating this all together. I think that's where the
discussion needs to go.
Andrew Rodney
http://www.digitaldog.net/
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