How are photo sidecar files associated with image files?
Asked 2/2/2018
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2 answers
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I’m trying to understand how sidecar files such as .xmp or .aae are linked to their corresponding image files. Is the association based on embedded IDs or other metadata, or is it simply that both files share the same base filename in the same folder?
I’d also like to know the practical implications when renaming, moving, or deleting files outside a photo app. For example:
- if I rename an image in the shell or Finder, do I also need to rename the sidecar file to match?
- how can I identify orphaned sidecar files?
- if a sidecar is deleted, does that just remove the edit history or does it break the original photo?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
8y ago
2 Answers
2
That part is pretty simple. The same file name (in the same folder) associates them (the two files with the same file name, but with the two different extensions). For example a Nikon file in Adobe:
DSC_0512.NEF is the Nikon raw data, perhaps 30 MB.
DSC_0512.XMP is the Adobe meta file containing the list of edits, perhaps 8 KB.
When the raw app renames the file name, it renames both of them. When it deletes or moves the file name, it deletes or moves both of them. If you delete (or otherwise remove) just the one XMP file, you simply delete the list of all past edits, so the state of the raw file becomes unedited then.
Originally by user38978. Source · Licensed CC BY-SA 4.0
user38978
8y ago
0
Generated from our catalog & community — verify before relying on it.
In the common sidecar workflow described here, the association is simple: the image file and sidecar are matched by the same base filename in the same folder.
Example:
- DSC_0512.NEF = original image/raw file
- DSC_0512.XMP = sidecar with edit metadata
Photo software typically keeps them together automatically. If the app renames, moves, or deletes the image, it will usually do the same to the sidecar.
If you do this manually in the shell or Finder, you should also rename or move the sidecar so the base names still match. If they no longer match, the software may no longer find the sidecar.
An orphaned sidecar is generally just a sidecar file whose matching image filename is no longer present in that folder.
If a sidecar file is deleted, you are usually deleting the stored edit instructions/metadata, not the original image data itself. The image remains, but the software will treat it as unedited unless those edits exist somewhere else in the application’s catalog or library.
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