[Digikam-devel] Fwd: Re: gamma conversion, raw data format

[Gerhard Kulzer]

On Wednesday 20 February 2008 you wrote:
> 2008/2/17, Arnd Baecker <arnd.baecker at web.de>:
> >
> > On Sun, 17 Feb 2008, Gerhard Kulzer wrote:
> >
> > > Dave's reply - as expected!
> > >
> > > Gerhard
> >
> > Yep. So we have to do the gamma conversion ourselves it seems.
> > Could this be done directly in KDcraw ?
> >
> > Would this then address
> >   https://bugs.kde.org/show_bug.cgi?id=146393
> > ?
> 
> 
> Yes, and no. Add Gamma adjustment is easy to do in Color Managements image
> editor plugin, but this is not the real problem : to have an auto gamma
> adjustement as in 8 bits color depth  with 16 bits color depth...
> 
> Guillaume,  Dave ask to use pnmgamma like this :
> 
> dcraw -c -4 dscn0320.nef | pnmgamma -cieramp > gamma.ppm

I toyed with it today with the traditionally difficult Canon RAW files and profiles.  
dcraw -w -c -q 3 -4 -p "~/.color/icc/6101_lnd.icc" img_1377.cr2 | pnmgamma -cieramp |pnmtopng > img_1377.png

The images come out quite good ( in the sense: close to jpeg from the camera). From there it then quite easy to make the real adjustments on the RAW file (as opposed to creating a finding an image at all).

Gerhard

> why not to make a new option in libkdcraw to do it ?
> 
> Actually, this reminds me of Guillaume's patches,
> >   http://bugs.kde.org/show_bug.cgi?id=142055
> > ... ;-)
> 
> 
> 
> Yes, and i have tested all patches  in my computer. Files are ready to  be
> applied on  svn. Files are attached to this mail :
> 
> - KDE4 : patches against libkdcraw, Rawconverter plugin and digiKam. No
> problem relevant.
> - KDE3 : patches against libkdcraw, Rawconverter plugin and digiKam.
> Warning, this require to release libkdcraw 0.1.4 efore to release
> 0.1.5kipi-plugins (currently in RC2 stage)
> 
> So, you need to talk with Angelo if you want to do it now, or after than
> kipi-plugins 0.1.5 is released...
> 
> Of course, B.K.O 142055 can be closed as well (:=))). but patches improve
> very well white balance adjusments with RAW files, not auto gamma in 16 bits
> color depth.
> 
> Nota : Guillaume this patch is really great. Thanks again...
> 
> Gilles
> 



-- 
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