Today’s Question: I want to export a Lightroom catalog from one computer to another. Will the exported catalog merge with the existing one or replace it? I want to merge them and not lose any file or photo in either one of the catalogs.
Tim’s Answer: When you export a catalog from Lightroom, you will have a separate catalog file that will not be automatically merged with any other catalog. However, it is quite easy to merge two catalogs into a single catalog in Lightroom. The result will be a single catalog that contains all of the photos and information from both of the catalogs you merge together.
The process I recommend involves first exporting the catalog you want to merge into another catalog, and then importing that catalog into your “master” catalog. This approach is not necessarily the most efficient method (since it involves making an additional copy of your catalog and photos, which might not be necessary), but it is an approach that helps reduce the risk of mistakes.
First, open the catalog you want to merge into your master catalog, and select the photos you want to export. You might, for example, choose “All Photographs” from the Catalog section of the left panel in the Library module, and then choose Edit > Select All from the menu so that every image in the catalog is selected. Then choose File > Export as Catalog from the menu to bring up the Export as Catalog dialog.
I recommend using an external hard drive as the destination of the export operation, which makes it easy to make the catalog and photos from the “source” catalog available on the computer where your “master” catalog is stored. Specify a name for the exported catalog, using a name that will make it obvious what this catalog is being used for, such as “Catalog from Italy Trip to Merge with Master Catalog”. Also be sure the “Export negative files” checkbox is turned on, so your photos will be copied along with the catalog. You can also choose the option to “Include available previews” and “Build/Include Smart Previews” if you’d like to copy those files to the destination as well. When you have established the settings for the export, click the Export Catalog button at the bottom-right of the Export as Catalog dialog to begin the process of copying the catalog and photos.
When the process is complete, the external hard drive you used for exporting the catalog can be connected to the computer where your master catalog is stored. Launch Lightroom and open the master catalog (if it isn’t opened by default) and choose File > Import from Another Catalog from the menu. Navigate to the folder where you exported the source catalog, and select the “lrcat” file and click the Choose button.
In the “Import from Catalog” dialog you can make sure that the checkbox is turned on for the “All Folders” option, so all exported folders will be imported into your master catalog. Choose the “Copy new photos to a new location and import” option from the File Handling popup, and then click the Choose button to bring up the Choose Folder dialog. Navigate to the top-level location where you want to save all folders, such as the external hard drive you use to store all of the photos contained in the master catalog, and then click the Choose button to set that location as the destination. Then click the Import button to being the process of importing your exported photos into your master catalog.
The result, once again, will be that your master catalog now includes the photos you exported from the source catalog, along with all of the information you updated in the source catalog. At this point, once you have updated your backup of your photo storage and master catalog, you can discard the photos and catalog that were the source of your merge operation.
I discussed the process of merging multiple Lightroom catalogs in the April 2013 issue of Pixology magazine. If you’re a current subscriber to Pixology and would like a copy of this issue, simply send an email requesting this issue to firstname.lastname@example.org. And if you’re not already a Pixology subscriber, you can get more information here: