Originally posted by Canada_Rockies Lightroom does not modify the original file. It merely stores a script containing the changes you want before exporting the file.
That is not fully correct. For JPEG, TIFF, PNG, PSD and DNG files, Lightroom can/will save metadata directly in the files.
Of course LR does not modify the original image content, but the embedded XMP data is modified.
For all other supported files metadata will be written to sidecar XMP files next to the original photo.
With DNG files there is also the option to update modified preview and metadata in the file.
If a user wants to keep JPGEG, TIFF, ... untouched (not modified) there is no real chance with LR.
Write protection does not help, because LR reports an error in this case.
The requriement to use XMP sidecars can have multiple reasons:
- Backup process and speed
- Protecting original files
- Principle
- Avoid placement of proprietary data in original file
Regarding point 4, all LR edit data is proprietary and cannot be used by other software including some other Adobe software.
Why should I "pollute" my valuable original files with proprietary data and make the backup process too complicated and with overhead.
I like to use XMP sidecars for ALL my original media files. With DNG and LR this looks impossible.
Other tools like GeoSetter, JPhotoTagger, Imatch, Idimager, PhotoSupreme, ... can respect this requirement.
In another forum I read about the proposal to keep always two DNG files: One original DNG and a working DNG copy for editing.
This workaround is of course feasible, but is a big waste of storage and still complicating the regular backup process.
Peter