[Digikam-users] How do you generate good quality jpegs from raws quickly, automatically ?

Martin (KDE) kde at fahrendorf.de
Wed Dec 23 19:56:28 GMT 2009

Am Mittwoch, 23. Dezember 2009 schrieb Linuxguy123:
> This is a follow up to my "How does digiKam do raw conversions for
>  the slide shows ?" post from earlier today.
> So... I shot 600 raws at a wedding last weekend.  In digiKam the
> previews of these files look awesome.  Apparently they come from a
>  jpg embedded in the raw file.
> I need to convert the raws to jpegs.   I also have another 2,000 or
>  so raws to convert.
> The problem with converting raws to jpegs automatically is that
>  they almost never look as good as the preview images.  Please
>  don't tell me to shoot jpgs alone because when I spend a lot of
>  time on an image I can get it looking a lot better than than the
>  preview image, especially if the white balance is out and I
>  happened to shoot a grey card image from which to adjust the white
>  balance.  This happens frequently when I shoot in mixed lighting
>  situations, which happens from time to time.
> If I were a lazy man I would just extract the jpgs from the raw
>  files. But that seems like a waste given that we have all these
>  fancy raw converters and all the glorious raw pixel data sitting
>  in the raw file.
> I've used a number of tools (ufraw, Raw Studio and the digiKam
>  tools) and they usually come out looking pretty horid.  I can't
>  figure out why. The white balance is usually way out, the
>  saturation usually needs adjustment and sometimes even the
>  exposure is off.  I can fix all this stuff, but it takes a lot of
>  TIME.  I'm looking for something that doesn't take a lot of hand
>  tweaking.
> This raw conversion issue is a big problem for me.  Its the main
> bottleneck in my whole photography workflow, now that I have
>  digiKam anyway.  Before everything was a bottleneck.  Now only raw
>  conversion is.  digiKam rocks !
> FWIW, I have raw images from a D50, 40D and 450D.
> So how do you convert your raws to jpgs automatically and get a
>  good result, ie something close to the preview jpg ?  I would
>  prefer to use the tools in digiKam but will consider using outside
>  tools and eventually write a plugin to use them in digiKam.

I usually use UFRaw to set exposure, white balance etc. and safe it as 
ID file only (ID file contains settings only and is much faster to 
save than a jpeg or png). After that is done, I run ufraw-batch with 
the ID files (which can take very long).

I have created a curve which matches (almost) the EOS30D one. I use 
the EOS standard icc profile with gamma set to 0.45 and linearity to 
0.1. Additionally I set saturation to 1.1 and enabled auto black-point 

Most raw files looks pretty good with this settings. If many pictures 
can be developed the same way, you can use one ID file for many raw 
pictures. But I take the extra time to set some values for every 

My results mostly looks better than the embedded jpegs. Color is a 
little less intensive but I think more accurate.


> Thanks

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