Is processing information stored in the DNG?

[sapnho]

I was wondering where the processing information of DNGs is stored? In the DNG file itself or in the Lightroom catalogue?

[clee01l]

The correct answer to that question is 1) Maybe & 2) Yes.
The processing adjustments are always stored in the LR catalog along with all other metadata, flags and static collection memberships. When Save metadata to file is checked or by forcing it with {Cntl/Cmd}{S}, processing adjustments along with all other metadata are written to the DNG header, but not flags and static collection memberships.

[sapnho]

Ah, thanks. I was trying to understand the impact of a loss or corruption (yes, I backup) of the Lightroom catalogue. So assuming, I have save metadata checked, the DNG files themselves, can be used without having to redo the entire processing history?

[Brad Snyder]

.... and with a DNG, there is an additional choice {save the metadata and update the embedded preview}, which improves (to some degree) the usability/interchangeability of the DNGs with non-Adobe apps.

A second order concern is with backups, DNGs are big files, and metadata writes are little bitty trivial data changes. But depending on how your backups are configured, you may be doing a lot of backing up of large files, with the consequent bandwidth and time implications, to capture those little changes.


Ooops, I posted over top of your response. To your second question, yes, the DNGs by themselves, with the embedded data are enough to rebuild with (except for the couple of items Cletus mentioned)

[clee01l]

Ah, thanks. I was trying to understand the impact of a loss or corruption (yes, I backup) of the Lightroom catalogue. So assuming, I have save metadata checked, the DNG files themselves, can be used without having to redo the entire processing history?

Yes, but you lose those things that are stored only in the catalog like flags and static Collection membership. And of course, you also lose all dynamic collection criteria.

[sapnho]

A second order concern is with backups, DNGs are big files, and metadata writes are little bitty trivial data changes. But depending on how your backups are configured, you may be doing a lot of backing up of large files, with the consequent bandwidth and time implications, to capture those little changes.

That's a really good point as I do most of my back-ups online. However, the upload bandwidth here is about 10GB a day, so although that's not fast, it's fine.

[sapnho]

Yes, but you lose those things that are stored only in the catalog like flags and static Collection membership. And of course, you also lose all dynamic collection criteria.

That's seems acceptable as the biggest possible risk..