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Author Topic: questions re catalog backup and writing to xmp files or using dngs  (Read 7006 times)

CynthiaM

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I have some questions regarding how everything you do in lightroom gets backed up. By default LR does not write changes to xmp files. So what happens to any develop changes, keywording, rating; do they become part of the catalog? If you should have to restore a catalog in which metadata changes are not written to xmp, the restored catalog should restore all of your develop, keywording,rating, i.e metadata changes?

The reason I ask is because I had always been under the impression, perhaps mistakenly, that if you don't write these changes to xmp, then they are written to the original file which made me nervous, figuring anytime you write to the file you run the risk of corrupting it. But if LR is writing these changes to the catalog, then the original raw file remains untouched?

What happens if you convert to dng? Do the changes get written to the dng file or to the catalog?

I'm thinking that my understanding all of these years has been erroneous. Recently it has been pointed out to me that you take a hit in performance when writing changes to xmp. So if I have been wrong all of these years and if the LR changes are not written to the file but to the catalog, is there a way to safely get the data that sits in all of these xmp files in my harddrive into the catalog?
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Cynthia Merzer
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Denis de Gannes

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Re: questions re catalog backup and writing to xmp files or using dngs
« Reply #1 on: August 27, 2015, 10:25:22 am »

BY default Lightroom writes everything you do to the Catalog file. Backing up your catalog will preserve all your work.
Writing to .xmp or to DNG is a user option. The major benefits of writing to .xmp and DNG is to allow sharing of info between other Adobe applications.
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CynthiaM

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Re: questions re catalog backup and writing to xmp files or using dngs
« Reply #2 on: August 27, 2015, 11:06:12 am »

BY default Lightroom writes everything you do to the Catalog file. Backing up your catalog will preserve all your work.
Writing to .xmp or to DNG is a user option. The major benefits of writing to .xmp and DNG is to allow sharing of info between other Adobe applications.

So writing to xmp or dng is in addition to the changes being written to the catalog, not instead of?
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Cynthia Merzer
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john beardsworth

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Re: questions re catalog backup and writing to xmp files or using dngs
« Reply #3 on: August 27, 2015, 11:20:18 am »

So writing to xmp or dng is in addition to the changes being written to the catalog, not instead of?

It's in addition, wholly optional, and it doesn't include all your Lightroom work - eg flags, virtual copies, stacks, history steps, assignment to collections are not included in the xmp. Backing up your images plus the catalogue file (the lrcat file) means you have all your work backed up, without any need of xmp files.
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eliedinur

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Re: questions re catalog backup and writing to xmp files or using dngs
« Reply #4 on: August 27, 2015, 12:40:11 pm »

Also, LR never writes to other makers' proprietary Raw files. If the xmp option is exercised (or ACR is being used in PS) the xmp metadata is wholly external. However, if the file is DNG, of which Adobe is the proprietor, the xmp is internal.
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CynthiaM

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Re: questions re catalog backup and writing to xmp files or using dngs
« Reply #5 on: August 28, 2015, 10:08:59 am »

Thanks for all of your responses. The answers were helpful.
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Cynthia Merzer
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rob211

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Re: questions re catalog backup and writing to xmp files or using dngs
« Reply #6 on: August 31, 2015, 01:36:04 pm »

And BTW I don't think that these days that writing to the images and/or sidecars really slows down Lr that much. Anyone have any recent experience with that?
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RikkFlohr

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Re: questions re catalog backup and writing to xmp files or using dngs
« Reply #7 on: September 01, 2015, 10:30:18 am »

Also, LR never writes to other makers' proprietary Raw files. If the xmp option is exercised (or ACR is being used in PS) the xmp metadata is wholly external. However, if the file is DNG, of which Adobe is the proprietor, the xmp is internal.

One minor correction: ('never' should read 'almost never') If you have Lightroom Catalog Preferences>Metadata set to "Write date or time changes into proprietary raw files" AND you go to Metadata>Edit Capture Time and change time or date on a file, that change can be written back to the raw file. It is the only situation in which Lightroom will overwrite a raw file.
« Last Edit: September 02, 2015, 09:33:52 am by RikkFlohr »
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stingray

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Re: questions re catalog backup and writing to xmp files or using dngs
« Reply #8 on: September 02, 2015, 12:39:02 am »

A possible work around.

With Lightroom in Grid mode, drag the folder or selection of images you want to import over the Lightroom grid and release. Lightroom will enter Import mode and will have your folder or files preselected. Then apply your normal import settings or presets.

This is not ideal, but saves me a lot of time and avoids Lr second guessing what drive to import from.


Apologies .... posted in error to wrong discussion. Happy to delete or for someone else to delete.
« Last Edit: September 02, 2015, 06:36:57 am by stingray »
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