How Does the Lightroom Catalog Work?

how does lightroom catalogue work

Lightroom is my new favourite piece of photo editing software. Until a year ago, I had never touched it for fear of change from Photoshop. I felt that Photoshop was superior, as it has a greater arsenal of tools. But in truth, the majority of those I never needed and Lightroom is far better at cataloguing and organising photos. In fact, my edits are even better in Lightroom thanks to the integration of raw editing and quick sharpening and noise reduction. It is now a rare occasion that I take photos into Photoshop for processing.

how does lightroom catalogue work

Understanding the Lightroom Catalog

One of the greatest things about Lightroom is how its catalog database works. If you want a great way to organise your photos, then this is it. The catalog records 3 key pieces of information for each photo:

  • A link to where the photo is stored
  • Instructions for how you have chosen to process the photo
  • Any metadata, such as keywords, to help organisation

The first point, the reference to a photo’s location, is one of the most important things about Lightroom. You don’t actually touch the original file, but instead create a link to the file from the catalog. Lightroom conducts its edits on previews of the original file. All your processing adjustments are recorded as metadata, meaning that the edit is entirely non-destructive – you can always go back to the original file.

When you export a file for publishing online or sending to a printer, for example, Lightroom will take a copy of the original file and apply your edits automatically. Then it will save a new, processed copy of the photo wherever you specify. Then you are left with both the original and your processed image.

You may have also noticed that even when the photo’s original file is not present on your computer (maybe the hard drive is disconnected), you can still view and edit metadata for the photo. This is because Lightroom creates thumbnails of your library – although you won’t always be able to view a high resolution copy, as it is not permanently stored in the cache. You can’t make any edits to the photo without the file being present, though.

lightroom catalogue
The ‘!’ indicates the original file is not connected.

Backing Up the Catalog

Don’t forget to back up your catalog though. If you don’t, then you may lose everything should the catalog corrupt or you damage your computer. In the same way that you back up your photos, you should make external backups of your Lightroom catalog. It contains all of your precious edits and metadata additions. You really don’t want to lose these, or you’ll have a lot of work on your hands.

By default, Lightroom will prompt you to back up once a week when you exit the program. You can change this frequency though, by navigating to the following section:

  • Windows: Edit > Catalog Settings
  • Mac: Lightroom > Catalog Settings

In there, you’ll see an option for adjusting the frequency of this prompt. You’ll also see the location of the back up and where it is stored. You can store it locally for ease, but you should remember to copy this to an external backup periodically. In fact, you should also mirror your backup, just like you should do with your photos.

backup lightroom catalog
Adjust the frequency of your Lightroom backup prompts.


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