[Digikam-users] How does digiKam do raw conversions for the slide shows ?

[Martin (KDE)]

Am Mittwoch, 23. Dezember 2009 schrieb Mark Greenwood:
> On Wednesday 23 Dec 2009 17:14:29 Gilles Caulier wrote:
> > 2009/12/23 Mark Greenwood <fatgerman at ntlworld.com>:
> > > On Wednesday 23 Dec 2009 16:59:45 Linuxguy123 wrote:
> > >> I shot 600 raw images at a wedding this past weekend.
> > >>
> > >> I downloaded them into digiKam, tagged ~ 200 of the best and
> > >> ran them in the digiKam slide show for the gift opening the
> > >> next day.  They looked awesome.  Everyone was very pleased.
> > >>
> > >> Yesterday I tried converting some of the same raw files to
> > >> jpgs using the tools in digiKam.  They didn't come out nearly
> > >> as nice, due to issues with white balance settings, exposure,
> > >> etc.
> > >>
> > >> How does digiKam generate the images for the raw files it
> > >> displays in the slide shows ?   How could I easily generate
> > >> jpegs that look as good as the images in the slideshow ?
> > >
> > > I would assume that for the slideshow Digikam is using the
> > > embedded JPEG data from the RAW file and not the RAW data. You
> > > can extract the embedded JPEG using exiftool (though I forget
> > > how, try googling it) but that really defeats the object of
> > > using RAW. When you use RAW you are expected to do all the
> > > white balance etc adjustments yourself. The embedded JPEG has
> > > the camera's built-in adjustments already applied. If you're
> > > going to use the embedded JPEG you may as well just shoot JPEG
> > > in the first place.
> >
> > Yes, it use JPEG preview. Fast and usefull...
> >
> > > There's no "easy" way to get good results from RAW, you need to
> > > put in the effort to 'develop' each shot yourself. With
> > > practice you'll soon be getting *better* results than the
> > > images in the slideshow.
> >
> > and it's long to decode.
> >
> > > However, all that said, I've found that the tools in Digikam
> > > sometimes don't cope very well with RAW files - you need
> > > accurate icc colour profiles for your camera, for one thing.
> > > Most people seem to like ufraw for RAW processing, and it does
> > > seem to give more "accurate" results than Digikam does.
> >
> > I don't use ICC and i always shot in RAW (minolta). Results are
> > fine with a some adjustement (saturation). I use auto gamma and
> > 16 bits color depth of course.
> 
> You have just filled in the missing piece of the puzzle for me I
>  think... so I don't need an icc profile for my camera even if I
>  use RAW? The RAW import tool somehow knows how to interpret the
>  colour information? If that is the case then I think I now
>  understand why I can't seem to get the results I expect when I'm
>  using colour management. I think I actually don't need it at all.

Hallo Mark

You don't need colour management to develop raw files. digiKam (and 
all others raw converter) uses a default colour pattern if there is no 
icc one available. The difference is mostly marginal. The advantage: 
you don't have to fight the colour management battle, the 
disadvantage: You loose some parts of colour control.

Martin

> 
> Mark
> 
> > I never use UFRAW : too complicated for me... and GTK (:=)))
> >
> > Gilles Caulier