Understanding Adobe Lightroom Classic Catalogues and Libraries
Hello everyone! I want to thank regular reader Mike for the reminder that it is past time for me to go over the Lightroom storage model as new or newer users of Lightroom often are not clear on how things work, and that Adobe is not particularly clear on this topic.
Moreover, everyone and their cat appear to have a best practice that tells how they do it, but not why they do it. The model that you choose is entirely up to you and perhaps this article will help you decide on which way to go.
The Catalog*
I have been around for a while, and remember public and school libraries that had paper index card files. These are all now computerized and are probably faster and less prone to misfiles, but they don’t illustrate the concept of the catalog as well.
In an index card type catalog, each book had its own entry on an index card. That card would tell you a bit about the book and where to find it physically based on a standard library classification system and location in the stacks based on the Dewey Decimal system. This model is brilliant because it is so easily consumed. What Adobe did with the Lightroom catalog is similar.
In the Lightroom catalog, and to be clear, I am talking specifically about Lightroom Classic, the rich desktop style application, not the cloud version, a similar model is used. The catalog holds information about the photograph and also has a location indicator of where the image file is stored. Just like the old school library, the catalog does not contain the image, only a pointer to where the image actually is.
The Lightroom catalog also has a default sorting mechanism, which is by date of image creation. This is a simple and straightforward system, although some users find it less than intuitive, months and years after the image gets stored. We will come to that in a bit.
Since there are no images stored in the catalog, there is a secondary storage location called the Lightroom Library. This is a location where the actual images get stored. By default it uses a date hierarchy, following the year - month - day structure. Each image is stored by default in a date named folder.
The process to get images into the catalog and stored in the library is done in the Lightroom Library module by using the function IMPORT. There are multiple options for import but to make entries in the catalog and to put images in the library you need only choose COPY on the IMPORT screen. This will create a new entry in the catalog for each image and then copy the actual image file from the source, most often a memory card, to the properly dated folder for the image. If all the images were made on the same day, they end up in the same folder, but if they were made on different days, they end up in folders specific to the day of creation. It really is that simple.
Unfortunately this date oriented storage model is found to be unintuitive to many users. Lightroom does offer the ability to rename the folder to anything that you want, but you MUST do that renaming from within Lightroom if you want the catalog to be accurate. This is identical to moving a book in a traditional library to a different classification. If you just move the book, the catalog will not be updated and will be wrong. In digital imaging, if you rename a folder outside of Lightroom, its catalog system will not know and the image will show as Missing. This is also true if you move an image file outside of Lightroom. The Lightroom catalog will not know about the move and will say that the file is Missing. The simple solution to these potential errors is to only move files or rename folders from within Lightroom. If you do this, your catalog remains intact and images can readily be found.
Collections
Collections are a separate kind of indexing system that do not physically change the location of files or the names of folders. Collections are pointers to images using whatever naming convention that you want. There are many “best practices” out there for renaming files and folders inside Lightroom, but to be blunt, I don’t use or recommend any of them. Instead, I use Collections. Collections are stored in the catalog but because they are merely pointers take up almost no space and do not physically contain any images.
Let’s say that you enjoy making images of automobiles. Instead of renaming every folder of images made, or even renaming individual files, create a collection. Perhaps you have an affinity for Plymouth Superbirds. You have images of Superbirds taken at different times and places. Rather than moving files and folders in the Library module, make a Collection called Plymouth Superbirds and then simply drag the image into the collection. The physical file does not move. The Collection contains to actual images, only pointers to the physical location of the image. Now to look at all your Plymouth Superbird images, you would simply click on the collection called Plymouth Superbirds and it will show every image regardless of physical location that you added to the collection.
Take this a step further. You also have a collection called Ford Mustangs and a collection called Old Cadillacs. You can put all those collections into an entity called a Collection Set. A collection set does not contain physical images, or even pointers to single images, it just contains pointers to the collections stored within it.
In my example, I may shoot the same model many times over a period of years. Let’s say that the model’s name is Sarah Smith. I will make a collection for each shoot, let’s imagine I have a collection called Sarah Western, a collection called Sarah Casual, a collection called Sarah Formal and a collection called Sarah Headshots. It would be convenient to put all those collections into a collection set called Sarah Smith, which is precisely what I would do. Now I can find all my work with Sarah Smith in one place and also drill into a specific collection for a more limited selection of images. The other beauty of a collection is that the same image can exist in multiple collections simultaneously. This is completely similar to the boxes of alternative indexes found in the libraries of my youth. There would be an index of authors, an index of subjects all independent, none of them containing any physical books but all pointing to the proper storage location in the stacks. So simple and so easy.
Where Do I Keep My Catalog and My Library (Libraries)
Your Lightroom catalog can get quite large depending on the type of Previews that you store. Adobe allows the catalog to be stored on any locally attached disk drive and defaults to the boot drive of the computer. Some people have computers with relatively small boot drives and keep their catalogs on a locally attached separate drive. This works just fine, but I recommend that you keep the catalog on a fast responding drive for performance reasons.
By default, Lightroom will try to establish the library of actual images on the same drive as the catalog. The libraries contain the actual images so they get huge quickly, and in general you do not want these stored on the boot drive. The good news is the Lightroom does not care where the library is physically stored, so you can put that on an external local drive or even on a network attached storage system or storage area network device. Read performance for images is less critical than for the catalog, so for economic and scale reasons, most Lightroom users choose fast spinning drives with decent sized cache to hold the library. In reality, there is nothing that requires that you have only one library location, so long as the catalog can point to the right one.
It used to be that some folks recommended multiple Lightroom catalogs. While you can do this, the necessity to do so no longer exists from a performance perspective and switching catalogs while not difficult, definitely falls into the pain in the butt bucket.
Conclusions
As I mentioned, there are many ways to approach how you catalog and physically store your images and there are multiple ways to help you find images after the fact such as keywords and keyword hierarchy in addition to file and folder renaming, beyond collections. I confess that I use collections exclusively and aggressively and that works for me. I would much rather spend time making images and editing the keepers than in maintaining storage models and renaming stuff. Whenever I import files, I add them to a Collection at time of import (it’s a checkbox on the Import screen) I can either create a brand new collection or choose to store the images in an existing collection. Once imported, I can drag the preview image into any number of different collections if needs be.
You have to choose the system that suits you best. There are in fact some people who prefer to copy the image files into their own folder structure completely independent of Lightroom. If you do that, the only change you make on Import is to choose ADD instead of COPY because the files are already where you want them and all you want is for Lightroom to be able to point to them. Your choice. For me, Collections are fast and easy and less work and more efficient than file and folder renaming.
* for my Canadian and British readers, I am aware that I am misspelling catalogue, however I chose to use the spelling used by Adobe in Lightroom Classic
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