Adobe Photoshop Lightroom CC - Manual (Page 94)

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Last updated 4/20/2015
Chapter 7: Managing catalogs and files
How Lightroom catalogs work
What's in a catalog?
A catalog is a database that stores a record for each of your photos. This record contains three key pieces of information
about each photo:
1 A reference to where the photo is on your system
2 Instructions for how you want to process the photo
3 Metadata, such as ratings and keywords that you apply to photos to help you find or organize them
When you import photos into Lightroom, you create a link between the photo itself and the record of the photo in the
catalog. Then, any work you perform on the photo — such as adding keywords or removing red eye — is stored in the
photo's record in the catalog as additional metadata. When you're ready to share the photo outside Lightroom —
upload it to Facebook, print it, or create a slideshow, for example — Lightroom applies your metadata changes, which
are like photo-developing instructions, to a copy of the photo so that everyone can see them. Lightroom never changes
the actual photos captured by your camera. In this way, editing in Lightroom is nondestructive. You can always return
to the original, unedited photo.
The Lightroom catalog versus a file browser
The way Lightroom works is different from a file browser such as Adobe Bridge. File browsers need direct, physical
access to the files they display. Files must actually be on your hard drive, or your computer must be connected to a
storage media that contains the files, for Adobe Bridge to show them. Because Lightroom uses a catalog to keep track
of the photos, you can preview photos in Lightroom whether they are physically on the same computer as the software.
The advantages of the catalog-based workflow
The Lightroom catalog workflow provides two distinct advantages for photographers:
1 Your photos can be stored anywhere
2 Your edits are nondestructive
Lightroom offers flexibility in managing, organizing, and editing photos because your photos can be anywhere — on
the same computer with the Lightroom application, on an external hard disk, or perhaps on a network drive. Because
the catalog stores a preview of each photo, you can work with your photos in Lightroom and see your editing changes
as you work. And all the while, Lightroom doesn't touch your original photo files.