Adobe Photoshop Lightroom creates a database to help you organize your digital photography. You must understand how this databasing system works to truly master the Adobe Photoshop Lightroom program. Every image in your Adobe Photoshop Lightroom Catalog is a unique reference point that records the details about one specific photo. Think of this reference point as if it were an index card in an old-fashioned library’s card catalog. Each index card in Lightroom records the file’s name, the path to the file inside of your hard drive, and all of the photograph’s metadata.
My students, and loyal readers of this site, know that I am a big fan of the single Lightroom Catalog philosophy. In my opinion, most photographer’s should stick to one, and only one, Lightroom Catalog. I believe that most digital photographers will get more out of this software if they stick to a single index for all of their photography. Searching for an image can be fast and efficient in Photoshop Lightroom as long as you only need to search through a single index. Things get complicated, and less efficient, when we need to search through multiple indexes to find an important image. By deliberately using only one Catalog, there is only one place to look for anything photographic!
Still, Adobe Photoshop Lightroom is a professional-grade application. The Adobe software engineers do not believe in “one-size fits all” solutions and they have not have not placed artificial limits on this program’s capabilities. Unlike other image management programs, Adobe Photoshop Lightroom will allow you to create an infinite number of catalogs and to store them wherever you want. This is a great blessing for some photographer’s. I am not one of them, but I must admit that there are times when I will intentionally create a second Lightroom Catalog for a specific purpose.
Perhaps a little more explanation is needed here. I feel like I need to make it clear when, and why, I might choose to create a second Lightroom index. For my photo storage, I use a super fast RAID 0 (Stripped) external hard drive. All of my photographs, and my main Lightroom Catalog, live on this external disk. I love this storage setup, and I have written a lot about its advantages elsewhere on this site, but there are times when I go traveling without this big external hard drive.
Truthfully, I often leave my main external disk at home when I fly somewhere to teach a class or to shoot an assignment. Often I will just grab my camera bag, and my laptop, and go!
While I am out on the road, and away from my photo storage external hard drive, I usually create a temporary Lightroom Catalog so that I play with my new work. This mini-index, my “on-the-road temporary catalog” can be a great help but I don’t intend to keep it forever. I will merge this Temporary Catalog, and all of the images that it references, into my Main Catalog as soon as I get back home. Using a temporary index is handy when I am traveling without my main drive but ultimately I am going to delete it. This Lightroom Catalog will be deleted once it has been safely merged with my main index.
This video tutorial explains the merging process. This movie explains how to combine one Adobe Photoshop Lightroom catalog with another by using the Import from Catalog command. Let me remind you though that this is not my normal everyday routine. The standard Import Files from Disk command is the one that I use daily to copy new files over to my hard drive from a digital camera’s memory card. The Import from Catalog command is a feature that I use only when I need to preserve information like Collections, Pick / Reject Flags, and Virtual Copies.
I only use the Import from Catalog command when I need to preserve things that exist only at the Lightroom Catalog level. Since I automatically save all of my work down to the file’s metadata level, I only need to use the Import from Catalog command when I have created features like Collections which cannot be stored within the actual photographs.
Let me also caution you that this process works best if you use a consistent folder naming system. As you will see in the video, I always create the same parent folder and I always divide my files up using the exact same folder naming system no matter where I store my images. If you are consistent, and careful, then merging two Adobe Photoshop Lightroom Catalogs together is an easy task!
Check out this great tutorial from Adobe Evangelist Julieanne Kost for more help using the Import from Catalog Command.