7 Replies Latest reply on Jul 21, 2014 5:24 PM by DdeGannes

    Do NOT EVER enable XMP metadata when using DNG!

    N. Gollan

      I regard the raw data as something that should never, ever be mutated, not even the container it is stored in. Lightroom's behaviour to modify those files is, quite frankly, a horrible bug that needs to be fixed.

       

      Do not enable that option, it will only ever bring you pain and loss!

       

      Corrupting those files (and that's what writing metadata to them after an initial import does) leads to unnecessarily huge backups, and right now, after I've been stupid enough to enable the option, an incremental backup that should have lasted maybe 20 minutes pushing maybe 10 gigabytes  has been running for well over an hour, and will probably end up with a changeset of over 200 GiB. It also produced a situation in which I have an unresolvable data integrity issues: as long as those files are considered immutable, any change can be attributed to file system corruption, indicates corrupt image data, and a backup can easily be restored; with metadata in those files, there is no way to do that. So effectively, all integrity across the metadata write is lost!


      XMP sidecars are good. Including that information in exported files is good too. The current implementation is a horrible bug.

        • 1. Re: Do NOT EVER enable XMP metadata when using DNG!
          dj_paige Level 9

          I wouldn't call it a bug ... it was designed that way, it works properly given the design. You would like it to work differently.

           

          If your concern is the time it takes to do the backup and integrity of the original files, then don't  convert your RAWs to DNG. Then nothing is written to the original RAW files, the metadata is written to sidecar files of about 10Kb, and these small sidecar files are all that have to be backed up after the metadata is written to the sidecar files.

           

          I realize that this doesn't fix your current problem with data integrity. But it may help others (and you in the future) with the same concerns.

          • 2. Re: Do NOT EVER enable XMP metadata when using DNG!
            thedigitaldog MVP & Adobe Community Professional

            I take the opposite approach, I want all that XMP and more inside my DNG and I don't care about the backup time, it happens while I sleep. Further, LR has DNG data validation:

            DNG | dpBestflow

            Last thing I want are a huge pile of sidecar files, that's one reason I do work with DNG. I do want my DNG custom profiles embedded into my DNGs, and I do want a nice big JPEG of the current rendering.

            • 3. Re: Do NOT EVER enable XMP metadata when using DNG!
              john beardsworth Adobe Community Professional & MVP

              Review and adjust your backup routine. Backup the original DNGs when they are new, and routinely backup your catalogue. This gives 100% coverage of all your work. The DNGs recorded in the catalogue don't need backing up whenever metadata is written to them.

              • 4. Re: Do NOT EVER enable XMP metadata when using DNG!
                areohbee Level 5

                N. Gollan wrote:

                 

                XMP sidecars are good.

                Agree - sidecars should be an option for all file types.

                 

                N. Gollan wrote:

                 

                The current implementation is a horrible bug.

                Disagree - the way it works is intentional, so by definition: not a bug. Nevertheless I get the sentiment..

                 

                R

                • 5. Re: Do NOT EVER enable XMP metadata when using DNG!
                  DdeGannes Adobe Community Professional

                  I hear your grief, for me I am using Lightroom to process my raw files and one of the major reasons is the fact that I can use a workflow that does not include the use of xmp or dng.

                  Lightroom design by default reads and writes to the Catalog file all info is stored there and with proper backup can be kept secure. No hassle with sidecar files or having to read/write metadata to files, no having to think what is up to date info in the catalog or the file. My raw files are all supported by dozens of software packages for processing and I perceive no risk of them becoming obsolete. Backup of the raw files is simple. Usefulness of the xmp info created by Lightroom/ACR outside of Adobe products is minimal. If I have to make adjustments in PS CS I can use the "edit in feature" from Lightroom which does not need info from an xmp file.

                   

                  For me the functionality of Lightroom renders the use of xmp and dng unnecessary.

                  Others may find xmp and dng, useful, necessary, helpful and even critical for their workflow. I have no problem with this opinion.   

                  • 6. Re: Do NOT EVER enable XMP metadata when using DNG!
                    thedigitaldog MVP & Adobe Community Professional

                    DdeGannes wrote:

                    For me the functionality of Lightroom renders the use of xmp and dng unnecessary.

                    Others may find xmp and dng, useful, necessary, helpful and even critical for their workflow. I have no problem with this opinion.  

                    Nor do I (the other side) but, there's a lot more to DNG than just it's ability to move away from sidecar files. Lots more.

                    • 7. Re: Do NOT EVER enable XMP metadata when using DNG!
                      DdeGannes Adobe Community Professional

                      Yes Andrew I am aware and agree there are benefits for the use of dng but there are also cons, which I have to be aware of, since I use software that does not work with dng files.

                      I can see how the OP got caught with his xmp data getting "corrupted" because he was not fully informed on the use of dng files.

                      Often on the forums advice is given "convert to dng" without a word of caution to the user to become informed before proceeding, as if it is some magical file format