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[Openexr-devel] Embedding ICC profiles in OpenEXR
From: |
Geraldine Joffre |
Subject: |
[Openexr-devel] Embedding ICC profiles in OpenEXR |
Date: |
Mon, 21 Nov 2005 07:44:32 -0500 |
I've been to a conference on HDR-Photography and 3D-Visualisation in Hamburg
last week. The
audience was mainly professional photographers, so when Spheron talked about
their HDR
camera, they were asked about how the HDR files are color managed and whether
they have
ICC profiles (color management is very important for quality photography).
The answer was that the SheroCam HDR camera had been characterized but that no
ICC profile
is available for the HDR files produced. The only way to get an ICC profile is
to shoot an LDR
image so that the profile gets embedded in a 16-bit TIFF file. So, I intervened
to explain that a
newer version of the OpenEXR format makes it possible to define the
chromaticities of the RGB
primaries and white point, which means the camera just needs to populate the
chromaticities
attribute when writing the HDR file in order to get a 'color managed' HDRI.
However, from the discussions I had afterwards, I realized it might be more
convenient for a
photography workflow to have the chromaticities values available in the form of
an ICC profile
embedded in the OpenEXR file. The responsibility for creating and embedding the
profile would
be left to the application that produced the OpenEXR file -- the HDR camera or
the software that
created it from multiple exposures. The advantage is that the CMM of color
managed software
could directly handle OpenEXR files that have an embedded ICC profile.
Otherwise, additional
coding is necessary to extract and convert the chromaticities attribute for
correct handling by
the CMM.
I think it could be a good idea to add the ability to embed ICC profiles in a
future version of
OpenEXR, the same way it can currently be done with the TIFF and JPEG formats.
Thanks.
Geraldine Joffre
--
HDR Imaging for Photography
http://www.hdrsoft.com
- [Openexr-devel] Embedding ICC profiles in OpenEXR,
Geraldine Joffre <=