I'm looking into converting my Canon RAW files (CR2) to lossy DNG purely due to storage limitations. I only shoot RAW and in my country storage (physical or cloud) can still be pretty expensive. I shoot a lot and I've about 4TB of RAW images. I have no space left.

I liked most of what I've heard about DNG, except the fact that changes that I make using Lightroom (my software of choice) go either into the catalog or into the DNG file. I really like the idea of having a separate file with metadata regarding my editing. If feels a lot more portable and safer, since if I want the "virgin" file I can just delete the XMP.

Is there a way to achieve the sidecar workflow with DNG?

  • \$\begingroup\$ 4TB of CR2? 100.000 pictures? Do you ever cull your images? You would save a lot of storage that way. \$\endgroup\$
    – xenoid
    Commented Jan 11, 2020 at 21:29

1 Answer 1


I hope you are aware of all the disadvantages of lossy DNG conversion. The instrument you need is exiftool. With the command below

exiftool -xmp -b -w xmp filename.dng

you can extract the xmp file and you will have as result in this directory filename.dng and filename.xmp For automation you provide directory name instead of filename:

exiftool -xmp -b -w xmp directory/with/a/lot/of/dng

Also be aware AFAIK this xmp file will not be read from Lightroom when load the DNG file. To reset you need to open the file in Lightroom, Develop module, select image and press Reset button (bottom right corned)


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