The Lightroom catalog is an amazing creation that makes my life easier every day.

However, it is also a hard topic to get your head around if you’re not familiar with a photo catalog setup.  And it is the number one source of questions in my Lightroom classes.

This catalog is a database that stores 2 types of information about your photos:

  1. The location of the photo – where you saved the photo on your hard drive (where the photo”lives”)
  2. Data describing the photo (including shooting settings, time, date, AND the edits you’ve made to a photo inside of LR)

Note that the Lightroom catalog does not store the photos themselves.  In other words, the photos that you look at inside of LR do not live inside of LR.

Why is this a good thing?

One of the things I like the best about LR is its crop function.  You can change the crop on a photo anytime you want because the pixels are never thrown away.  (Unlike Photoshop Elements.)  You can even undo a crop that you made last year.  How is this possible?

Because the catalog stores the location of the photo and a description of it, but not the photo itself.

When you crop a photo, this is what Lightroom says to itself:  “The file located at Hard Drive/My Photos/2012/April/Clients/Smith/SmithCakeSmash45.jpg should be cropped to an 8×10 beginning the the upper left corner.”  However, because the photo doesn’t live in LR, the file isn’t actually cropped.

Anything you do to this photo from within Lightroom will have this crop applied.  And you can do a lot from within LR:

  • Upload to Facebook
  • Email
  • Print at home
  • Create a slideshow or web gallery
  • Create a book at Blurb
  • Burn a CD

Ok, so what happens if you need to use that photo outside of Lightroom?  For instance, you want to upload photos to a print lab for printing.  You can’t do that from within Lightroom.

Exporting is essentially “sewing” the actual photo together with the list of edits that the catalog holds.

To export a photo, simply right click and select Export.

You will see a window like this where you can tell Lightroom what to name the new file, where to save it, how large it should be, whether to watermark it, etc.


Have you ever noticed that you don’t save your photos while editing in Lightroom?  Why is that?

Because the photos don’t live inside of LR, so there is nothing to save. The catalog stores the location of the photo and a list of edits made to it.  Those edits are stored the minute you make them.  So there is nothing to save.

Here’s an interesting experiment if this isn’t clicking for you.  Look at a photo in LR and make some crazy, really obvious edits to it.  You can undo them later.  Next, navigate to the location on your hard drive where this photo lives.  Use either Windows Explorer or the Mac Finder to do this.  Open the photo and look at it.  There are no changes there, right?

The only way to put a photo on your hard drive with the LR changes is to export it.  However, you ONLY need to export if you’re going to do something with itthat you can’t do from within Lightroom.

Another question that often comes up about the catalog is about the question marks that you might see on photos.  Like the one at the top right corner of this image:


That question mark means that you confused Lightroom.  You moved the photo on your hard drive without “telling” LR where to find it.  Or you deleted it or renamed it or put in in a new folder.  Regardless, LR can’t find it.

Any of those changes should be made within Lightroom, not directly on your hard drive.  And yes, when the question mark appears, you will still see the thumbnail image in Lightroom’s catalog (LR saves a small thumb of every photo in the catalog), but you won’t be able to edit it.  Or, unfortunately, recover it if you’ve lost the photo.

 Now, if Lightroom crashes, it’s possible to lose the edits stored in your catalog.  You need to back it up.  Which we’ll cover tomorrow.  Sorry to leave you hanging on that cliff, but I think it’s enough for one day to cover the basics of the catalog in Lightroom!