[Digikam-users] Color management.. again

Caulier Gilles caulier.gilles at kdemail.net
Sat Jun 17 17:56:07 BST 2006

Le Samedi 17 Juin 2006 15:53, Per Aalrust a écrit :
> Hi Gilles,
> > Like you. I'm shoot my picture in AdobeRGB with my Dynax5D and convert it
> > later when i open the MRW picture in image editor using 16 bits color
> > depth mode and ICC color management enable.
> 	So you are only using digikam 0.9.x version?

Yes, of course, i'm using 0.9.0 in production, but i'm developper (:=)))

> 	The conversion is done by 
> dcraw, like in 0.8.x version?

yes, but there is a new way. Let's me explain :

1 / you can convert RAW file like in 0.8.x using 8 bits color depth. You don't 
need color managementin this case because dcraw set the color balance 
automaticly. I never use this mode because this is not the better color depth 
workflow to convert a raw file... but it's simple and fast.

2 / you can convert RAW file using 16 bits color depth. This is the better RAW 
workflow, but it's more complicated : the decoded RAW file in RGB is in 
linear mode and there is no color balance ! This is why we need color 
management in this case, to use the LUT of the camera (icc camera profile) 
and the LUT of color workspace (icc workspace profile). Color management is 
important here because without using it, the RAW decoding result will be a 
black hole.

Minolta color profile are very good and work very well with digiKam. The MRW 
result in 16 bits are similar than DImage win32 application give. This is not 
the case of Nikon and Canon. I suspect that icc color profile for this camera 
are uncomplete (no gamma correction LUT). For that, i recommend to use the 
icc profile files provided with bibble program (free using during 15 days). 
The profiles of bibble program are installed into your computer 
in /usr/share/apps/... 

A nice day


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