What is a Lightroom Catalog?

///What is a Lightroom Catalog?

When it comes to photo management software there is good news and bad news. The good news is that there are only two types of software options to choose from, Catalogs or Browsers. The bad news is they can be a little confusing if you are not careful in understanding the differences. If you are using Adobe products (which is what we cover mostly here at Photonerds University) then you are given both types of options. Adobe Lightroom, a cataloging system; Adobe Bridge, a file browsing system. In order for you to understand what a Lightroom Catalog is, we should begin by discussing the differences between cataloging and browsing.


By definition, the word ‘Browse’ means the act of casual looking or reading. In the case of Adobe Bridge, it allows you to look at the files and folders which live on your hard drive without the need to go to the hard drive directly. Think of it like walking into a Barnes and Nobels Book Store and looking at all the organized book shelves. The problem with this option is that if a Book was sold and not replaced, you would never know by looking at the shelf that a book was missing. This is true in the sense that if you had moved or deleted a folder or file from your hard drive, a browser will not tell you that fact.


In the case of a catalog, you would create a systematic list or record of inventory. That inventory in this situation is of all your photographs. This list remains intact at all times (unless you make a change to the list) and the record is there to help you locate a file within the directory. What’s great about this catalog is that if a file goes missing (because you may have moved, renamed or deleted a file) the catalog will be able to notify you that your photo is missing and you could go looking for it.

A catalog is not only limited to file or folder locations. A catalog is designed to go beyond this fact and can also identify characteristics about a photo. For example, the date and time of a photo, what camera you used, what lens you used, what focal length you used and more. This is classified as metadata and this metadata is also stored within the catalog.

What’s very important to know is that your photos are never stored within the Adobe Lightroom Catalog exactly. Lightroom is only creating and keeping track of the files as a form of text. It knows what files and where they live in relation to your hard drive. It is also creating and keeping track of a preview file that resembles your image. Think of it as a photo of your photo but it is not your actual photo. It’s simply a visual representation of your photo. If your photo or folder is moved, deleted or renamed after the fact, you will still see a visual representation of your photo but it will be shown as missing and you will need to find and relink the image after the fact.

Important Information

This may or may not seem a little confusing at the moment but it really isn’t. If you are a PC user, you have been using Windows Explorer to find files. If you are a MAC user then you have been using Finder to find files and folders. Both of these options are Browsers and should be familiar to you.

Catalogs are completely different as previously mentioned, if you remove, delete or rename an image or folder your file will not be accessible. The reason is that Adobe Lightroom is still looking at the original file or folder information and does not know the changes you have made outside of the software program. Missing files or folders will be identified as a question mark or exclamation mark. You will not be able to edit the photo and you also will not be able to export the photo to share with others.

If you have made changes via edits to the original file, applied additional organizational elements like stars, flags or colors, if keywords have been used…none of these things will only be available once the original file has been found and relinked.

How do we avoid bad things from happening?
  • If you need to rename an image? Do it from within Adobe Lightroom
  • If you need to move a file to another folder? Do it from within Adobe Lightroom
  • If you need to create a new folder? Do it from within Adobe Lightoom
  • If you need to move a folder? You guessed it, do it from within Adobe Lightroom
  • If you want to delete a folder or file. Again, do it from within Adobe Lightroom

Lastly, make sure that you are backing up your Lightroom Catalog. There is a lot of infmation stored inside of this catalog and the more work you do the wortst it would be if your catalog is to get lost or corrupted.

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