The Ultimate Guide to Lightroom Catalogs - Digital Darkroom Academy

The Ultimate Guide to Lightroom Catalogs

Lightroom works a bit differently than other softwares. If you don’t understand how Lightroom thinks, then it can land you in a lot of trouble with your photos and you may end up doing do things about managing your photos that aren’t necessary at all. While it is a great tool for retouching, one of the most important features of this software is its image management capabilities. Those image management capabilities are built on what is known as a catalog-based system. In this post, we go in depth of what exactly a Lightroom catalog is and everything there is to it. 

This is a long guide to Lightroom catalogs. Before you continue, bookmark this page now because you’ll want to return to it later. You can jump to the different parts of the post using the links below:

Part 1 – What is a Catalog? [Published: December 28th, 2017]

Part 2 – Managing your Catalog [Published: January 23rd, 2018]

The Ultimate Guide to Lightroom Catalogs [Part 1]

What is a Catalog?

I like to explain what a Lightroom catalog is, with the help of The IKEA Analogy. What exactly is a catalog when we’re not talking about Lightroom? The catalogs that you get in your mail? Or the ones that you browse through to see what you’re going to buy for the holidays? Well, they are simply a list or record of things; usually products that you might want to buy. Let’s take an example. Let’s say that you wanted to get a new chair for your living room and luckily you had just received an IKEA catalog in your mail a few days ago and you start browsing through it. Now, when you’re browsing through that catalog, you are seeing what each and every chair looks like; there’s also a certain set of specifications mentioned with every kind of chair that’s available, it’s size, it’s colors, it’s weight and all kinds of different things that let you get a better idea of what the product actually looks like. Now, the chair is not in the catalog itself. The catalog only shows it’s preview and any other specifications there are to it, but the actual chair would be in the IKEA showroom; not in the catalog. And if I make any changes to the catalog, that wouldn’t do anything to the actual chair in the showroom. I mean, if your kid went ahead and started coloring one of the images of the chair in the catalog, that doesn’t mean that the chair sitting in the IKEA showroom is going to start changing color. That just doesn’t make sense.

A product catalog contains all the information about the product
A product catalog contains all the information about the product

A Lightroom catalog works in a very similar way. When you import a photograph into Lightroom, what you are seeing is just a preview of it; the actual file of the photo you took is sitting somewhere in your hard drive; wherever you decided to place it. Any of the changes you make within Lightroom never actually affect the actual file at all. Instead, a record of all the changes you make within Lightroom is getting stored in what’s known as the Catalog file.

The Lightroom Catalog contains all the information about your image.
The Lightroom Catalog contains all the information about your image.

Just like the IKEA catalog had certain specifications mentioned under each of their chair’s headings, like the size, color etc., in the same way, your Lightroom catalog contains four pieces of important information about each of the photo within the catalog:

  1. Location: The location of the photo’s file on your system.
  2. Adjustments: Any of the changes you’ve applied to it within Lightroom.
  3. Metadata: Any metadata associated with it
  4. Preview: A limited preview of the photo (which are stored in a separate file than the main catalog)

The actual file of the photo, whether that’s a RAW or JPEG or any other format, is not stored in this catalog, but only the information listed above. So, actually, a catalog file is nothing but a text record. The image files themselves, will actually reside wherever you decided to place them. and that is why you would notice that the size of the catalog file isn’t as large as some of the photos that you take with your camera.

The only way that a Lightroom catalog is different than the IKEA analogy mentioned above is that when you import the photos into Lightroom, it builds a connection or a link between the record of the photo and the actual photo. While it isn’t actually making changes to any of the original files, it is linked to them. This is so that in case Lightroom needs to access any information (such as a larger preview) from the actual files that it didn’t bring in when it was importing the files, it can access that information now. I explain this a little later in the post but it is very important that outside of Lightroom, those files are not changed, moved or renamed, because well, if Lightroom tries to go to that location to find the file and that file is not there, or doesn’t have the same name, the connection of the Lightroom catalog with that file is now broken and you won’t be able to do much with only the preview you’re seeing within Lightroom.

Why is a Catalog More Effective than a Regular File Browser?

1. Store your photos anywhere

As has been explained above that a Lightroom catalog is only a record of certain information about the photographs and not the actual photographs themselves. A regular file browser, such as the Mac Finder, Windows Explorer or Adobe Bridge, needs direct and physical access to the files that they show, whether they are on your computer’s hard drive or to any attached media. Lightroom, on the other hand, through its records in the catalog, can enable you to preview and even make changes to those files even if they are not physically present within your system. So, you could be on an airplane with your laptop and your photos could be in a hard drive sitting at home and you would not only be able to preview your files, but if you enable what’s called Smart Previews, you can even make changes to those photos.

2. All Edits are Nondestructive

If the files of your photos are at home, and you are sitting in an airplane editing them; that means you’re not touching the original files at all and the original file is never affected by any of the edits you are making. If you’ve ever worked with Photoshop, it sometimes so happens that you’re working on a photograph, you apply an adjustment or reduce its size or you crop it; and you accidentally run the Save command, overwriting the original in the process. Now once you’ve done that, you don’t have the original full-sized file and instead what you have is the cropped version or the one that’s reduced in size. Lightroom prevents this scenario from ever occurring. Any adjustment, or crop or reduction in size that you apply to the photograph is stored as a record in the Lightroom catalog and never actually affects the original file. In this way, any changes you make within Lightroom are non-destructive allowing you to go back to the original at any point, in case you mess something up.

Where Should You Store Your Catalog File?

When you open Lightroom for the first time ever, Lightroom will open its default catalog which will be named “Lightroom Catalog.lrcat” and by default, it places it in your Pictures folder, which on a Windows machine would be C:\Users\[USERNAME]\Pictures\Lightroom and if you’re a Mac user then you will find your Lightroom catalog on this location: [USERNAME]\Pictures\Lightroom

The Lightroom Catalog folder will typically contain 2 files; but if you use Smart Previews, it’ll contain a 3rd file too
The Lightroom Catalog folder will typically contain 2 files; but if you use Smart Previews, it’ll contain a 3rd file too

You can decide to either use this default catalog created by Lightroom, or decide to create your own. But where should you store that catalog? Should it be on your computer’s hard drive? Should it be on an external hard drive? Should it be on the network or the cloud? The only limitation that Lightroom places on this is that it can’t be stored on a network drive. Other than that, you can place it anywhere. 

While having the catalog on your computer’s internal drive will ensure the fastest performance, having it on the external drive that contains your photos is going to make your life much more portable. You may have one main computer that you use Lightroom with all the time, but if you want to open the same instance of Lightroom on your laptop or another computer elsewhere, all you will have to do is simply plug in your hard drive to that computer and open that catalog file there and everything will open up the same way it would on your main computer. You will not be dependent on a single computer to view your instance of Lightroom. Just something to consider here would be to use a fast hard drive so that Lightroom’s speed isn’t affected too much. So, my recommendation about where you should store your catalog is an external hard drive.

Another option is to store it on cloud, but I don’t recommend it. You can sign up for a service like Dropbox, Google Drive or Microsoft OneDrive and store your catalog there. You will have portability with this too. All you will have to do is to have your Dropbox, Google Drive or Microsoft OneDrive set up on multiple computers and whichever computer you’re using, you can open up the catalog file on that from the cloud folder. One very important thing to note here is that, you won’t be able to use the same catalog file on two computers at the same time. So, if you’re using it on one computer, you will have to close it from there first to be able to open it on another computer. The other thing here is about speed. Having your catalog on a cloud service would mean that if you’re using Lightroom on the other computer, you will have to wait before it’s completely synchronized; and if the catalog is large, which it usually is, then that could mean waiting a lot before you can see the most updated version of the catalog. Sometimes that could mean never shutting down either of your computer because they’re both busy synchronizing the catalog. So, while having the catalog on the cloud may sound like a good option for portability, it has its downsides.

Finding the Default Catalog on your Hard Drive

If, for some reason, your default catalog is not on the path mentioned above, you can find your catalog file using another method. You can simply go to the Edit menu (PC) on top. That will be the Lightroom menu on a Mac and choosing Catalog Settings from there.

That will open up the Catalog Settings dialog box, where you can see the location of your catalog. There is also a Show button and if you click on that button, it’ll open up that folder on your hard drive.

The Catalog Settings dialog will tell you where you can find your catalog file.

Creating a New Catalog

If you want to work with a completely new catalog, you can crate a new one. Creating a new catalog is fairly simple. In the menu bar on top, just go to the File > New Catalog.

Creating a new catalog is very simple
Creating a new catalog is very simple

A window will pop-up asking you where you want to store your new catalog. You can select the location, choose a name for it and click Create. Once you do that, it’ll create a folder in that location by the name you chose and inside that folder will be three files. A .lrcat file with the same name, A .lrdata file which contains all the previews. If you use Smart Previews, there will also be a third .lrdata file which will contain all the Smart Previews.




Learn how to use Lightroom to get organized, create amazing photos and cut your editing time in half.

Moving, Renaming or Deleting Your Photos – The Jon Snow Effect

This is probably where most Lightroom users make mistake and end up in a lot of trouble with their photographs. We have discussed already that when you get your photographs into Lightroom, they’re never really in Lightroom. They’re just linked to, or just referenced to. A lot of people don’t understand the implications for that; and end up with missing files and missing folders. They start seeing the dreaded exclamation marks (!). All their photos. Gone! And then they frantically turn to the online world for help. Here’s a glimpse of what you would find in almost every Lightroom related Facebook group:

If you don’t take the time to understand what’s going on, this could be you. As discussed above in The IKEA Analogy, the files of the photos are never inside the Lightroom catalog. They are just linked to, or referenced to.

The error for missing files appears when that link is broken. You see the dreaded exclamation marks. Why does that link break? If those files are changed outside of Lightroom, the link gets broken. If those files are renamedmoved or deleted outside of Lightroom, the link between Lightroom and that file is broken. I like to call this The Jon Snow Effect. In this situation, Lightroom turns into Jon Snow. Lightroom knows nothing!

Basically, Lightroom has no idea that a file has been renamed, moved or deleted. Lightroom goes to look for that file, but because that file is no longer in that location, or doesn’t have the same name, it can’t find it. When it can’t find it, Lightroom gives the error for ‘missing files’. I have a simple rule to make sure I don’t get this error, that I don’t activate The Jon Snow Effect:

Once in Lightroom, everything within Lightroom.

Once you have your files inside of Lightroom, if you need to move them, rename them or delete them, do it from inside of Lightroom. That way, Lightroom knows of all the updates that have happened to the files, and no links are broken. If you do it from your Windows Explorer or Mac Finder, you turn Lightroom into Jon Snow. The computer tells simply tells Lightroom, “You know nothing, Lightroom!”

So, what do you do if you have accidentally triggered The Jon Snow Effect? What do you do if you are seeing the missing files error and the exclamation marks of death? I take you through that in this video below.

Subscribe on YouTube

Is there a limit to the number of photos a catalog can hold?

Back in the day when Adobe launched the earliest version of Lightroom, catalogs would become really slow once they reached 50-60 thousand images. But, Adobe has made great improvements over all these versions. Adobe knows that photographers shoot a lot and can have a huge number of photographs in their Lightroom catalog. Adobe knows of people who have literally over millions of photographs in their Lightroom catalog and they still work fine. So, I think, no one really knows if there’s a limit; but I think if a catalog can contain over a million images, most of us are good to go! I’ve been doing photography for over 12 years, I shoot quiet a bit and I still don’t have a million. Not that a million is the limit, anyway.

Should You have One Catalog or Many?

This is one of the most asked questions by photographers. Should you have just one main catalog? Or many different catalogs? To answer this all important question, I have a theory called The Pencil Box Theory. Your catalog is kind of like a pencil box that we used to have in school. There were all kinds of different pieces of stationery in that pencil box like the pen, pencil, eraser, sharpener, a compass, a pair of scissors maybe, a paper cutter and whatever you needed for stationery back at school. Now if someone was to ask you how many pencil boxes should I carry with me? One, two, five? In most cases, you would just go along with having one. You don’t go and have a separate pencil box or pouch for each one of the different stationery items.

Do you have a separate pencil box for each stationery item?

With the earlier versions of Lightroom it was commonly known that if you had reached a certain number of images, say 20,000, in your catalog, it would significantly slow down the overall performance of Lightroom, and for you to ensure that it kept running at a good speed, you had to divide your images into a lot of different catalogs. But that’s not the case anymore. Lightroom doesn’t have a limit to the number of photographs a single catalog can hold; neither does it slow down performance based on how many photos are in one catalog. Adobe itself recommends that you only have one catalog. There are a number of ways in which you can sort, filter and organize your photos within one catalog and with some thought and practice, you will realize that you can find ways to manage all your photos with just one main catalog.

But, what would be the situation where you might need to create multiple catalogs? Well, carrying the above analogy forward, let’s say that along with the regular stationery, like pencils and erasers that everyone carries with them, you were taking art as a class too, and you had to carry paint brushes along with a watercolor set as well. In that case, you might go ahead and carry all those brushes, and the watercolor set, in a separate box or pouch. Because that’s something different than your regular stationery and you only need it in art class and don’t need it in any other class. So, there can be situations where you might want to create multiple catalogs. A good example that I came to know about for this was a photographer who did all kinds of different photography, like family portraits, weddings, corporate photography and all that; but for his own personal work, he also did artistic nudes. Now, if he had those images in the same catalog, he might end up in a very awkward situation where he would be presenting his corporate portfolio to a board of directors of a company and he accidentally clicks on a folder that had his work of nudes in it. So, to avoid a situation like that, it’s a good idea to have all of this kind of work in a completely separate catalog. So, for most kind of work, it would be best to consolidate it all in one catalog, but if you need to separate stuff that you wouldn’t want to overlap with other stuff, creating a new catalog would be the way to go.

The Ultimate Guide to Lightroom Catalogs [Part 2]

How to Merge Multiple Catalogs?

If for some reason you have created multiple catalogs and you want to merge them now, you can do that very easily. While I did recommend above that you use only one main catalog, but there could be places where you may temporarily create multiple catalogs.

For example, when I go on a trip, I take my laptop with me. My main master catalog is in an external hard drive that’s usually connected to my desktop. I don’t take that external hard drive on my trips. What I do instead is create a temporary catalog on my laptop, which just has the photos from the trip. I can then merge it with my main master catalog on my desktop when I am back.

Merging catalogs is pretty straightforward. In the menu bar, go to File > Import from Another Catalog.

Alternatively, if you press the Alt key on a PC, or the Option key on a Mac, the Import… button in the Library module on bottom-left changes to Import Catalog.

The Import and Export button change to Import Catalog and Export Catalog
The Import and Export button change to Import Catalog and Export Catalog

It will ask you which catalog do you want to merge into the one that’s currently open. Choose your catalog and Lightroom will bring everything into this one. All your edits, all your flags, star ratings and color labels would come in as these two catalogs are merged.

A side note is that, if you’re importing from a temporary catalog, you can delete that catalog if you want. Everything’s now in your main master catalog and you don’t need the temporary one anymore.

Setting Up a Default Catalog

When you open Lightroom, how does it know which catalog to open? You can set up a default catalog so that every time Lightroom starts, you’ll know which one will open up. In the menu bar above, just go to Edit > Preferences or if you’re on a Mac, that’ll be Lightroom > Preferences. Once the Preferences dialog is open, under the General tab, there’ll be a setting Default Catalog and a dropdown ‘When starting up use this catalog’. From that dropdown you can select a particular catalog you may want to open every time Lightroom starts. The other two options you have over there are to load the most recent catalog, or ask you every time Lightroom starts, which catalog is it that you’d like for to open.

Renaming a Catalog

There’s no option inside of Lightroom to rename a catalog, but you can do it using your default file browser (Explorer on Windows & Finder on Mac) to do it. If you’re not sure where your catalog file is, it’s explained earlier in this post, under the heading Finding the Default Catalog on your Hard Drive.

You need to make sure of a couple of things as you rename your catalog. First, make sure that catalog is not open by Lightroom. If it is, then close down Lightroom to do this.

Next, as you’re renaming the files, you will have to also rename the corresponding Preview file/folder and if there is one, then the Smart Previews file to the exact same name that you give to the catalog file (.lrcat) following the pattern of the corresponding files/folders. So, it’ll have to be something like this:

Old Name New Name
Default Lightroom Catalog.lrcat New.lrcat
Default Lightroom Catalog Previews.lrdata New Previews.lrdata
Default Lightroom Catalog Smart Previews.lrdata New Smart Previews.lrdata

In the case that you do not rename the preview files/folders, it won’t exactly break anything, but it’ll just have to re-create all the previews again every time you access a file. That only means it’ll take up extra time every time a preview has to be created.

Optimizing a Catalog

After a while of you using the catalog, as photos are imported into the catalog, some are deleted, you apply certain attributes to them, you change Develop settings; things inside the catalog may get jumbled up. Lightroom may end up having a hard time looking for information that it needs. Just like you need to clean your room every time it becomes messy, you will also need to optimize your catalog every few days or after any major operation.

Optimizing the catalog is a pretty simple process. You can go to the File menu and select Optimize Catalog. Once you do that, it’ll ask you for a confirmation. After confirming, depending on the size of your catalog, it’ll take some time to optimize the catalog. Larger catalogs will take longer whereas smaller ones may get done fairly quickly.

Shajee Aijazi

Shajee Aijazi is the founder of Digital Darkroom Academy. He helps people speed up their post-processing workflow and organize their photos in a way that they don't have to waste time managing it and they can focus on creating great looking images.

View all posts

Add comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

The Ultimate Quick Start Guide for Lightroom

In this free guide, I will take you through the basics of Lightroom to so you feel more confident.

Subscribe to Our YouTube Channel

Recent Posts



 A mini-course that teaches you a step-by-step system that you can use to take your photos from boring to amazing in no time.



Learn how to use Lightroom to get organized, create amazing photos and cut your editing time in half!