[Digikam-users] What am I doing wrong?

Daniel Bauer linux at daniel-bauer.com
Sat Aug 30 11:17:06 BST 2014

Am 30.08.2014 11:18, schrieb Stuart T Rogers:
> Well not sure how to do this.... the only command used was a watermark
> using text and no background at 20% size otherwise all default values
> and I renamed them and stored them in the same folder (album). The input
> images were standard jpegs from my Pentax K500 and the saved files were
> also jpegs. I looked for compression settings on the batch queue manager
> but cold not find any. Comparing the images afterwards showed the
> renamed ones at about 1.8 or 1.9MB but the same pixel resolution as the
> originals which seems to me that somewhere a compression setting of less
> than 100% was used but as I say I cannot find anywhere how to set this
> for jpegs in the batch queue manager.
> I cant send images that size to a mailing list.
> Stuart

I just did a small test and I see that indeed batch process does not 
respect the settings under

Einstellungen -> digikam einrichten -> Bilder speichern - JPEG-Qualität

(free tanslation: settings -> set up digikam -> save images -> jpg-quality)

I set there jpg-quality once to 100%, once to 5%. The results of a batch 
were exactly the same (in quality and in file size). So I /guess/ that 
digikam uses a fixed compression ratio in batch processes (when saving 
directly with "save as" indeed there is a huge difference between 5 or 
100%...). I think this is a bug, if someone wants to report it...

However, I do not use digikam to place watermarks, I use imagemagick 
command line tool. I can place any text (or image would be possible, 
too) in any manner and convert to any file format/compression I like. I 
have several scripts in my digikam root folder, open them in kwrite, 
adjust the needed, save as "once.sh" (which is executable) and run it 
from the digikam root folder...

My every-day-watermark-script looks like this:

> #!/bin/sh
> cd /to-where-the-selected-originals are
> mkdir topublish
> for bild in *.png
> do
> convert "$bild" -resize 1280x1280\> -quality 88 -interlace line -strip -font /path-to-for-example/arial__0.ttf -pointsize 18 \
>           -draw "gravity SouthEast \
>                  fill black  text 20,9 '© www.daniel-bauer.com' \
>                  fill white  text 21,10 '© www.daniel-bauer.com' " \
>           -verbose ./topublish/"${bild%.png}.jpg"
> done

(pasted as quote for line length, remove quote marks...)
You find all the tricks on http://www.imagemagick.org/Usage/



Daniel Bauer photographer Basel Barcelona
professional photography: http://www.daniel-bauer.com
google+: https://plus.google.com/109534388657020287386

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