3 Replies Latest reply on Jul 18, 2017 2:25 PM by JimHess

    How does Lightroom store DNG files?

    linda-o Level 1

      I thought that I understood that Lightroom is a catalog that does not actually store any images, but references them - references their location where you choose to store them on your computer. I was recently told that Lightroom DOES store DNG files, and it is as if Lightroom is keeping all of your original "negatives".


      So I tried an experiment:
      I imported photos in as .DNG files, and copied to my Desktop.
      I then deleted the deleted the file from the Desktop and closed Lightroom, thereby eliminating all images from my hard drive.

      When I reopen Lightroom, I see my photos in the Library.
      If I choose "Show in Finder" I get an error message, as expected, that the file does not exist. (correct, because I just deleted it)
      I am also unable to open the image using Photoshop, as, like above, it does not exist.


      This is my confusion:
      I can still edit that image within Lightroom, and export it as a .jpg.


      If this is the case, I can bring thousands of photos into lightroom as .dng files, then delete them all from my drive (thus saving tons of space), yet I have access to all of those images and can edit them and export them as .jpgs. 


      How is Lightroom accessing the image, if I have deleted the reference location? Where is that .DNG being stored? If I simply backup my Lightroom catalog, are all of my .DNG files then backed up? Is it true that the Lightroom catalog keeps all of my .DNG "negatives", and I just need to store my edited files, exported as .jpg images, on my hard drive?


      Thanks for any clarification!

        • 1. Re: How does Lightroom store DNG files?
          JimHess Adobe Community Professional & MVP

          Have you actually tried to edit and export a deleted image? All you are working on is the small preview that Lightroom has generated. If you try to export that image you are going to get a message that the file cannot be found. And if you go to the develop module there should be a message in the main editing screen indicating that the file is missing. You can't do anything productive with the Lightroom preview file. It's just a small preview. Nice try, but it isn't going to work. And, no, it isn't true that Lightroom keeps all of your DNG images. If you delete your DNG files, they are gone. End of story.

          • 2. Re: How does Lightroom store DNG files?
            linda-o Level 1

            Ahhh, I get it. A full image should be (from my Canon Rebel and how it is currently set) 17x11, 300 res.
            If I delete that image from my hard drive, then edit it in Lightroom, and then Export it as a jpg, the image comes in at 8x5, 300 res. So that would be the largest file you can get from using a Preview image.


            I am glad to have it verified that it is necessary to keep the original .dng file in a location on my hard drive.


            Thank you.

            • 3. Re: How does Lightroom store DNG files?
              JimHess Adobe Community Professional & MVP

              I think you'll find that if the original file is gone and you're trying to work with the preview only, you won't be able to do any editing and develop module and all of your export options aren't going to be available. The preview really isn't any value to you by itself.

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