How does Lightroom store data about photos?

Question

I've seen numerous mentions of Lightroom's database, or catalog, and having to back it up. Being used to Bridge and Camera Raw, I'm accustomed to seeing sidecar .xmp files alongside my RAW files. These can easily be backed up with my RAW files since they are actual files.Does Lightroom use sidecar files, same as Bridge, or does it use its own database for storage of image tags, metadata, etc? Or is it some combination?

Answer 1

Lightroom DOES use the same exact XMP files! In order to see/save your sidecar file, you actually have to perform a step that tells LR to write the file.

First, select the images you'd like to write XMP's for. Next, go up top to the menu bar and choose "metadata" --> "save metadata to file(s)".

You can also set LR to automatically write XMP's by changing your preferences in "Catalog Settings".

Lastly, if you do NOT save to XMP, your edits and metadata are all still there within Lightroom. You can work forever within LR, closing and reopening the program, moving between folders etc, without loosing those edits even if you never save to XMP. Edits and Originals get detached when moving files around outside of Lightroom. For this reason, best practices are to always save XMP.