[Digikam-users] Re: need advice re: format conversion

[Elle Stone]

Gilles, I think you said above that PGF stores metadata. Yet when I
used the digikam image editor to open a jpeg with lots of embedded
metadata and immediately save it as a PGF file (no editing done), and
use exiftool to look at the metadata, none of the important metadata
was written to the PGF file. Instead there were several lines of new
metadata regarding "MPEG" with information such as AudioLayer : 1
AudioBitrate : 48 kbps SampleRate : 8000
which as my little jpeg isn't an audio file, is confusing - this
metadata is totally made up out of thin air.

When I open the same jpeg with the digiKam image editor, but save as
tiff or png instead of pgf, all the jpeg original metadata is written
to the tiff and the png. Is the problem that I'm still stuck on
livexiv2-v0.19?

Tom, you asked, "what converted format would YOU use - PGF for Digikam
and PNG for Gimp, or PNG for both, or something else?" I keep my raw
(cr2) files as cr2 files and will continue to do so even if I
eventually decide to also use dng. I keep my camera-generated jpegs as
jpegs, just as they come from the camera.

When I use Gimp to process a camera jpeg file, I immediately save the
file as "file.xcf" (Gimp's native format). General advice, as others
have suggested: never process a camera jpeg original - always work
with a copy, and immediately save that copy in a lossless format
before further processing. If I want to work further with a file
outside of Gimp, I export as tiff (call me old school), but I'm
looking into using png because there are a lot of software
compatibility issues with tiff. If I'm done processing, I export as
jpeg or png for the web. Regarding PGF and digiKam, I'd use png
instead.

A little experiment:
Original jpeg: 37 KB (its an extracted preview, not a camera-generated jpeg)
Some file size comparisons, all files saved with digikam starting with
the original jpeg
Saved as lossless PGF: 265 KB (7 times bigger)
Saved as png highest quality: 251 KB
Saved as tif: 943 KB