[KPhotoAlbum] kphotoalbum method of storing Tags, description

[Miika Turkia]

On Tue, Jan 24, 2012 at 8:22 PM, Karl Schmidt <karl at xtronics.com> wrote:
> Dug around the web pages - I'm not finding the method kphotoalbum uses to
> store annotations, tags etc.  IMO the best place to store this information
> is in the file itself.
>
> I'm looking for a system that stores them in the picture file as EXIF or
> better XMP - is this what kphotoalbum does?

We use our own XML file to store all the information. All tagging is
in this single XML file.

> In my quest I read where people were complaining that gimp overwrote exif
> information - (I'm running Debian with gimp 2.6.10-1 ) Is this still an
> issue?

I haven't used Gimp in years but a quick test on Ubuntu 11.10 says
that this is not an issue anymore. The exif data is copied over to the
saved image (naturally changing the appropriate fields like
modification date).

> My quest is to find a good method of annotating photos, that won't become
> obsolete or unsupported over time (which means storing the tags and comments
> in the photo file via exif of xmp).
>
> I would love to read something that explains the pros and cons of EXIF vs
> XMP for annotating photos.

The trouble of writing annotations to EXIF is that the image is
altered with each write. Any error in writing the exif might spoil the
image, e.g. even truncate it to size 0. So we like to keep the
original images intact. (We actually detect moved images based on a
hash of the image so changes in exif data will fool KPhotoAlbum not to
recognize moved image as the same and losing the annotations of that
images.) Same goes with XMP and IPTC if the data is embedded into the
image.

miika