I am starting the process to migrate to Digikam and likely to Darktable later on. I am looking for sanity check for the strategy here.
I will start with migrated FILE.xmp files and I will match Digikam XMP setting to be compatible with commercial software. At that time, I should not use Darktable or RawTharphy since they will not see the XMP files and may create something that would conflict with the migrated files?
After the migration to Digikam is completed, I will change Digikam XMP setting NOT to be compatible with commercial software, and resave XMPs.
DK writing out XMP files assumes that Digikam DB is up to date. DK scans albums on startup, and I have “Monotor for External changes” enabled. Is that enough?
I will end up with groupings, where file basename is the same: FILE.jpg FILE.raw FILE.xmp FILE.jpg.xmp FILE.raw.xmp - how will DK know which image a XMP is associated with?..
I will backup and delete FILE.xmp files, restart & rescan with DK.
I assume later on I will find out that some parts of migration will need to be redone. Will things be messed up if FILE.xmp from the initial migration are still around and Digikam is temporarily switched to commercial (FILE.xmp) compatibility?
I have no issues with the using “the commercial compatible” xmp naming convention with RawTherapee or ART. As far as ART or RawTherapee are concerned (with my workflow) xmp files are input only and RawTherapee and ART never writes or rewrites an xmp file. Unlike Darktable, with RT and ART, the editting data is not written to an xmp file but rather to a pp3 or an arp file
I see a problem with iPhone generating .JPG and .MOV or Samsung’s Pro mode generating .JPG and .DNG pairs. Digikam’s XMP files seem inconsistent, perhaps attempting to match one or the other files in a pair.
You hit the exact reason why digikam and darktable use the <name>.<orig_ext>.xmp naming scheme for sidecars: there is no way to link the <name>.xmp to either the raw or the jpg file, based on the filename. It is possible to include a tag in the xmp file indicating the base file, but that would require reading the sidecar file (slowing down the program)
That should not cause problems with digikam’s native naming scheme. If you use the “commercial compatible” naming ( <name>.xmp), see above…
Then again, it’s fairly safe to write metadata to jpeg and dng files (as the format is well documented, contrary to raw files). So there’s less need for sidecars with those formats.
As for the system used by ART/Rawtherapee: you’ll still want keywords, captions and such in the xmp sidecars, and there are use cases for having different metadata for different file types (if only linking a source file, which makes no sense for raw files…)
@pixolier just a warning that switching xmp naming format is a lot of work and fraught with danger…
Once you switch to darktable format it’s very difficult to switch back. You should never let any software but darktable and properly configured digikam touch your files. It’s easy to have a software produce standard xmp’s and they you have forked xmp that are very difficult to merge. The dt import is one way.
Files with the same basename are considered copies for xmp. So it’s useful to have one xmp file for all identical copies in different formats (tiff, jpeg etc.) since they are identical they should have the same metadata. In xmp a different file should have a different basename or path.