todd_shaner_6660895's profile



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Fri, Mar 15, 2019 3:54 PM

Lightroom CC Lossy DNG Workflow Suggestion

(This is a companion to a similar post for
Lightroom Classic–Please do not merge.)

This proposal provides suggested changes to the Lightroom CC workflow to use full-size lossy DNG files for 1) Lightroom CC Cloud Sync, 2) image editing, and archive of the original image files. These suggestions are applicable and beneficial across the entire Lightroom Classic and CC Desktop, Web, and Mobile ecosystem. Full-size lossy DNG files are useful for both local and Cloud image editing, reduce the required local and Cloud storage space, and speedup file transfers without sacrificing image quality.

As higher megapixel cameras become more common the benefits of using lossy DNGs are even greater.


The current workflow allows storing the original image files locally and in Cloud storage. I suggest adding an option to sync full-size lossy DNG file copies to the Cloud to reduce the required Cloud storage space and transfer time. Also provide an option to move the larger original image files to an external drive. When the external drive is disconnected for field or home office use allow using the full-size lossy DNG file copy on the internal drive as Smart Previews.

I’ve done considerable testing of raw, JPEG, TIFF, Panorama DNG, and HDR DNG files using full-size lossy DNG export files for editing with no issues.


- Full-Size Review,Editing, and Export when the original files are not accessible (i.e.external drive disconnected and no Internet connection).

- Reduced File Size of approximately 1/4 to1/6 of the original file size and near equal to a 90 Quality JPEG file size. The smaller lossy DNG file requires 75% to 85% less storage capacity and by virtue of file size reduction both localand Web based file transfer speed are increase dby 400% to 600%.

- Quality Retention is very good with no“visible” quality difference observed between the original and the lossy DNG files I examined. Since Develop edits are not applied to the lossy DNG image file it performs the same as a normal DNG file with the majority of subjects and edits. More at the below link.

Certain image files(high ISO, underexposed) when applied with extreme settings may exhibit differences, but they should be the exception. The user then has the option to “back-off”some settings or wait until they have access to the original files on the external drive.

Since most professional and serious-amateur users prefer to keep their original files locally (rather than the Cloud) this offers a more palatable solution for both LR Classic and LR CC Desktop, Web,and Mobile apps.

Optional Archive Workflow

Provide an automated archive function for image files thathave been processed with no intention of further editing. Many high-volume commercial photographers export the original raw files to JPEG copies after completion of a client project and then delete the raw files. A better option is to create a Lightroom archiving routine that demotes the raw file toa full-size lossy DNG file copy as follows.

1) Replace the original raw file with a full size lossy DNG file including all metadata(keywords, develop settings, etc.) for secondary backup purposes. Associate the new full-size lossy DNG files with the entire Lightroom Desktop, Mobile, and Web ecosystem.

2) Provide a file type tag similar to what is currently used with Smart Previews to identify these as ‘Archive’ image files.


The smaller lossy DNGfile requires 1/4 to 1/6 the storage capacity and by virtue of file size reduction both local and Web based file transfer speed is increased by 400% to600%.


Adobe Administrator


10.9K Messages


143.5K Points

3 y ago

Thanks for the posts, Todd!

4 Messages


102 Points

2 y ago

Perfectly written Todd. I'm happy to see that there are others that have had the same thought process when it comes to the DNGs and LR CC.