Lightrooms lossy DNG compression technique saves 67% of your disk space!

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If you are a professional photographer, RAW files such as CR2, NEF etc. are probably your favorite thing. No doubt these files give you creative freedom but it comes with a cost. They are extremely large files that cost you large storage and hence a lot more money.

JPEG’s on the other hand is the best w.r.t storage needs but you definitely do not want the quality it offers.

Enter lossy DNG files; they are like a dream come true for photographers. It offers a compression capacity as that of a JPEG and quality almost like a RAW image (lossless DNG). The final file occupies only 1/3 the size of the original file, thus saving you 67% of the disk space.

Refer to this article to know more about Jpeg XS the new Image Compression Standard.

More about lossy DNG compression

The resulting file after compression does not have any artefact’s that a JPEG does. It also saves a good amount of data to allow you to process the images if you wish. So what you get is the benefit of a RAW file which occupies considerably less space.

The drawback is the slight loss in quality like noise in the shadows and patterning (Color cast) in highlights.

If you are worried about the loss in quality, you don’t have to use lossy DNG compression on all files. If you have a large number of pictures that you do not want to delete, but you want to have, this may be a good option for you. This way you can save a ton of storage space.

Now that you know the advantages of lossy DNG compression, let us learn how to convert RAW images using the steps below.

How do you convert RAW images into lossy DNG?

The following steps explain the process of converting existing RAW images to lossy DNG using Lightroom.

  1. In Lightroom, press Shift + G key to enter grid view
  2. Select the photos you wish to convert to DNG
  3. Go to Library > Convert photos to DNG
  4. In the dialogue box that appears, make sure you select the right preferences
  • Only convert RAW files – Select this checkbox to convert RAW files
  • Delete original file after conversion – Select this checkbox to delete original RAW files after conversion.
  • File type – Select a lower case extension
  • Compatibility – Choose the latest version, Camera Raw 7.1 and later
  • JPEG preview – Medium size preview will do just fine; by selecting full size, the conversion may take longer
  • Embed fast load data – This allows images to load faster in the Develop module, so it is a good idea to have this option enabled
  • Use Lossy Compression – Select this checkbox to convert RAW file to lossy DNG file
  • Embed Original RAW file – Leave this box unchecked. This option is provided to have the original RAW file in your converted DNG file but this will increase the storage size of the file significantly. If you want the original RAW files, save it as a backup.
  1. As a final step, click Ok to convert to lossy DNG. Be prepared for it may take a long time for the conversion to complete.

With these steps you can convert DNG files and save your valuable disk space. But, while doing this you need to be more careful. If in case ‘Delete originals after conversion’ was enabled, all your original RAW files will get deleted automatically after conversion and you cannot get it back. You will need to resort to specialized data recovery tools. You can use Remo Recover tool to recover lost RAW files after DNG conversion. Hence, make sure this option is not enabled, while during this conversion.

Should You Convert Lossy Images into Lossless Format? Read this article to know the answer.

Refer to this article if you want to know how to resolve the “cannot open DNG files in Photoshop” issue.

About the Author: John Harris

With a decade of experience in data recovery, John Harris, Senior Editor at Remo Software, is your go-to specialist. His focus includes partition management, Windows solutions, and data troubleshooting, delivering insightful content that serves both users and search engines. John's expertise shines through in illuminating blog posts, untangling data loss intricacies across diverse storage platforms.…