About Lightroom catalogs

Lightroom uses a catalog to track the location of files and remember information about them. A catalog is like a database that contains a record of your photos. This record is stored in the catalog and contains data such as preview information, links that indicate where the photos are located on your computer, metadata that describes the photos, and editing instructions applied in the Develop module. When you rate photos, add metadata and keyword tags, organize photos into collections, or remove photos from the catalog—even when the original photo files are offline—the settings are stored in the catalog.

All of this information enables Lightroom to give you flexibility in managing, identifying, and organizing photos. If you’re photographing on location, for example, you can import photos into Lightroom on your laptop, and then move the original photos onto writable media or storage devices, and continue organizing and managing your photos without worrying about filling up the laptop hard drive. You can then transfer the catalog to your desktop computer, preserving the changes you make and keeping track of where the photos are stored. The catalog that you import with photos from the on-location shoot would be a separate catalog from any other catalog that may be stored on the desktop computer.

Note: Although you can view photos in both Lightroom and Adobe Bridge, the two applications behave differently. To view photos in Adobe Bridge, your hard drive must contain the photos, or your computer must be connected to a storage media that contains the photos. This is because Adobe Bridge is a file browser that only displays readily accessible photos. The Lightroom catalog is a database that keeps track of the photos you import, so you can preview photos whether your hard drive contains the actual photos or not. To edit photos in Lightroom, however, the software does need to be able to access the stored photos.

By default, Lightroom loads the most recent catalog. You can open a different catalog by choosing File > Open Catalog, or you can determine which catalog is opened in the General preferences.

For more information on Lightroom catalogs, see Catalog FAQ | Lightroom.