Option to write/read sidecar (xmp) files for continuous interoperability with other applications/editors
This is clearly not a bug, but a feature request for easing life of many users (I think) who, like me, use Shotwell as their basic photography DAM, but also use some other apps for advanced editing. It would also be a nice complement to the already provided option to edit a photo with an external editor (RAW or not).
Here's what I have in mind, based on my usual workflow: I import all my photos in Shotwell, where I tag and rate them and sometimes do some basic editing. When I want to do some advanced editing, I open (from Shotwell) the photo with darktable. darktable is then able to read the photo metadata (if they are embedded in the file) and include them in the xmp sidecar file that it creates for the photo. At this point, from a metadata/database perspective, Shotwell and darktable have the same info for that photo.
Now, here's where the problem appears: If I change the tags/rating in Shotwell, this won't be reflected in darktable. The reverse is also true (after the first import/opening, darktable is only reading/writing in the sidecar xmp file).
A solution would be for Shotwell to not only be able to write the metadata in its own internal database and within the photo file itself (as an xmp tag), but also in a sidecar file, based on the common xmp standard, which is used not only by darktable, but also by other important DAM/editing applications, like digiKam and Lightroom. (For Rawtherapee, I understand that it is writing to a - non standard? - pp3 file, but it's not clear to me if/how it can read xmp files)
Here's some more info on xmp sidecar files used by other apps:
Thanks for listening!