Re: [CinePaint] Working with RAW data

On Sun, 23 Mar 2008 21:16:56 -0500 (CDT)
Bob Friesenhahn <[email protected]> wrote:

> On Tue, 18 Mar 2008, Claus Cyrny wrote:
> >
> > I'm just reading Kai-Uwe's text, "CinePaint -- 16-bit imaging. From 
> > digital camera to print" 
> > <http://www.behrmann.name/cms/cinepaint/bildbearbeitung/cinepaint_ccorrection.html>, 
> > since I would like to start working with RAW data in CinePaint. My 
> > question: Where can I obtain an ICC profile for the camera I'm 
> > using. It's a Canon IXUS 500 (not mine), and I
> 
> I don't think that there is any such animal.  ICC profiles require 
> that the device have entirely repeatable characteristics and be used 
> in an entirely repeatable environment.  Ordinary digital cameras will 
> not have repeatable characteristics due to the way that they 
> automatically adjust for each scene.  The only possibility is if the 
> camera is used in an entirely manual mode in a professional studio 
> where lighting and backdrops can be entirely recreated.  In that case 
> you would take photos of a standard calibration target and use 
> software to create the ICC profile.  The ICC profile created would 
> only be valid for the exact conditions it was created under.
>

That certainly is true if we consider only the raw sensor data.
But raw processing usually involves the application of a white
balance to bring the color data to some standard condition.  It is
upon this standard condition that a camera input profile can be
defined.  Thus, one profile can suffice for many different types
of real world scenes.

The whole issue can be quite complex but I refer anyone interested
to check out this somewhat convoluted thread on the UFRAW forum:

http://sourceforge.net/forum/forum.php?thread_id=1907019&forum_id=434060

As a possible source for color profiles and the associated problems
also check this thread:

http://sourceforge.net/forum/forum.php?thread_id=1954962&forum_id=434060

The main problem with digital camera profiles and raw processing
is that most camera manufacturers keep the exact details for their
products a secret.  Only their proprietary software is recommended
and the Open Source user is forced to employ approximations
and trial-and-error approaches.

FP


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