Stitching Panos in Lightroom - leftover bits

Was stitching some panoramas in Lightroom over the weekend and when I went to check something in the folder the original Raw images were in I noticed something completely unexpected - XMP sidecar files were created for each of the panos segments. I have Lr set up to store edits in the catalog so I wouldn't expect Lr to have created them. I'm guessing they're necessary for the stitch process (borrowed from Ps?), but I would have liked them to have been cleaned up afterward because one of these days the images in those folders will get archived off and I'm going to wind up with sidecar files that I'm not going to know or remember anything about and that's going to get confusing when I start to move catalog images off to my external drives and wind up with non-empty directories because the XMP files are still there!! There's no way I'd know where they came from if I hadn't stumbled on this.

Anyone else run into this? I'm definitely not digging the new feature. I haven't tested it yet to see if it happens with the HDR merge as well, so if you've done that please report back. What I now don't know is if I go and do additional edits on the pano piece-parts will the edit wind up in the catalog or are they in the XMP? If it's the sidecar then I lose all that when I move the image without it - and I'll do that because I don't know if it's there.

If they create the sidecars for use by the process why can't Lr simply check my preferences and if I don't create sidecars as a default just delete them when it's done? PITA.

BackdoorHippie said:

Anyone else run into this? I'm definitely not digging the new feature. I haven't tested it yet to see if it happens with the HDR merge as well, so if you've done that please report back. What I now don't know is if I go and do additional edits on the pano piece-parts will the edit wind up in the catalog or are they in the XMP?

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I had a problem last year. I had xmp turned on for a couple weeks without knowing why I might need it. (you helped me understand why I did not need them) My problem was that my backup software renamed all the xmp every time I edited the photos, appending numbers to each update of the side car. I thought I was going to have to manually rename all the xmp since it was the newest that were renamed and LR was looking at the oldest xmp that had not been numbered.
Long story short, I learned that Lightroom stores edits in both the catalog and the xmp if one exists. And if the xmp exists, it trumps the catalog. Normally they contain the same edits, but mine were out of sync because of the backup. So simply deleting all of the xmp brought back all my latest edits from the catalog. In other words, the existence of an outdated xmp overrode the catalog.
So with that in mind, my guess was that you could delete or ignore the xmp. I did a quick pano test. Yes, it created unexpected xmp. I deleted the xmp's. No issues. Edits remained on the segments and the final product. No new xmp were created if I further edited the segments. It still is a nuisance that they get left behind, but it should not be a problem if they get lost or you delete them like LR should have.

Did some digging and if you convert your RAW files to DNG (I used to - I don't any more) then the changes get stored in the DNG - no XMP's. Technically that's a "destructive" edit since your DNG is no longer original in that the "last modified date" is different from the "create date". Same thing with JPEG and TIFF files. This becomes an immediate problem if you need to preserve an unedited original for contest verification purposes. Long story short, Lightroom is not purely a non-destructive editor, and if you need unedited originals always back them up somewhere else.

BackdoorHippie said:

Long story short, Lightroom is not purely a non-destructive editor, and if you need unedited originals always back them up somewhere else.

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So even staying NEF and not converting to DNG, Lightroom can/will modify the original NEF and not just export to a TIFF when opening another app? I'm assuming that's when LR would make any modifications to a pure RAW file...

RocketCowboy said:

So even staying NEF and not converting to DNG, Lightroom can/will modify the original NEF and not just export to a TIFF when opening another app? I'm assuming that's when LR would make any modifications to a pure RAW file...

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That's the one case where it can't, which is where the sidecar files come in, to store whatever the heck it is that they need for the merge process that gets tucked into a DNG, TIFF, JPEG, etc..