A Lightroom ­catalog is much like an old-school card catalog in a brick-and-mortar library. It contains all kinds of information (metadata) about your images — their physical location on a drive, ­keywords, ratings and even Develop Module ­changes, but it does not contain the actual images any more than the card catalog in a library contains actual books. The Lightroom catalog simply references your original photos wherever they live on your system. A catalog file (ending in .lrcat) works in tandem with the previews file (ending in ­.lrdata) to display information and editing without ever ­touching your originals.

Because only one Lightroom catalog can be open at a time, and there’s no way to search across multiple catalogs, it’s best to have just a single Master catalog. Lightroom catalogs don’t automatically synchronize, so your work in one won’t be recognized by another unless you merge them. Lightroom has awesome tools to organize your images, but a multiple-catalog workflow greatly increases the possibility for confusion and error and, most important, robs Lightroom of its organizational superpowers.

Two Workflow Scenarios
One Master catalog is easy to manage if you have a single laptop that you travel with and also use as your main computer at home. In that case, a couple of beefy external drives can hold (and back up) your entire Lightroom Library wherever you roam. On a trip, you simply import new images to your master catalog and — voilà! — no merging required.

If you’re traveling with a laptop and have a desktop system at home, or if you don’t want to travel with your entire photo library, then you should have a single Master catalog, into which a temporary Trip catalog gets merged upon your return. Once merged and backed up successfully, the Trip catalog can and should be deleted. It’s a very bad idea to have multiple catalogs referencing the same original photos.

The Adobe Method of Merging

Of the many methods for merging catalogs, Adobe’s recommended process is the most straightforward.

STEP 1: From the Library Module within your Master Catalog, choose File>Import from Another Catalog, and navigate to the Trip catalog you wish to merge. In this example, it’s my 2016_RajaAmpat catalog, on my external travel drive. Lightroom will analyze the differences and similarities between the two catalogs, and open an “Import from Catalog” dialogue box.

STEP 2: In the Catalog contents section of the Import from Catalog dialogue box, uncheck folders you don’t want to import. You can also uncheck unwanted images from the Preview window.

STEP 3: In the New Photos ­section, choose an ­option from the File Handling drop-down menu. If your new photos are already where you want them to live permanently, then you can simply “Add to catalog without moving.” ­Lightroom will reference the new photos from their current location.

STEP 4: If you’ve been on a trip, you’ll likely pick “Copy new photos to a new location and import,” in which case you must select the destination folder for your new photos by clicking the “Choose” button and navigating to it in the ensuing browser. You can also choose “Don’t import new photos.”

If you’re merging ­catalogs that reference some of the same images, you have­ a few choices to make in the Changed Existing Photos section. Replacing “Nothing” will leave the Master catalog as is, ignoring shared images. Replacing “Metadata and develop settings only” applies metadata from the catalog you’re merging from to corresponding images in the master catalog. If you’re not sure which set of metadata is the most current, you can choose to retain both sets by creating virtual copies of the images.

Choosing the “­Metadata, ­develop settings, and negative files” option replaces not only metadata, but also the ­corresponding physical photo files referenced by the ­master catalog.

STEP 5: Click the “Import” button at the bottom of the window to start the process.

STEP 6: Go for coffee or a refreshing adult beverage. This process can take a while.

Adobe Lightroom Tips

1. Deleting a Lightroom catalog file does NOT delete images, just information about the images.
2. Backing up the Lightroom catalog on exit from Lightroom does NOT back up your images, just the catalog (.lrcat) file. It doesn’t even back up the previews (.lrdata) file.
3. Consistently maintaining an ­orderly folder structure makes merging easier. You can download a copy of my ­recommended folder structure here: bit.ly/GoAskErin_Structure
4. Search your computer for “.lrcat” and “.data” files to discover any obsolete or unintentionally created catalogs, then merge them into one Master catalog. Having multiple unmanaged catalogs is a recipe for disaster.

See all of Erin Quigley’s Editing Tutorials Here

Erin Quigley is an Adobe ACE certified digital-imaging consultant and an award-winning shooter. GoAskErin.com provides custom tutorials and one-on-one instruction for the underwater photographic community.