P: Import as Lossy DNG

The ability to convert images to lossy DNG (visually lossless) is a great way to reduce file size by ~90%. I recently freed up roughly 3TB of space on my RAID drive by using this feature, translates into probably thousands of dollars saved for me. For those using a laptop with limited storage, this can offer tremendous benefits to save on the cost and hassle of external SSDs. This feature alone can probably offset much of the annual cost of LR subscriptions for many users.

These images are very high quality (still true RAW files) and can easily be printed at a very large size. The results will be visually identical for the overwhelming majority of images and uses. I have tested a large number of images over the past year and been very impressed with the results. The quality easily supports very large prints (especially when using Topaz Gigapixel to enlarge - Super Resolution does not currently handle these images nearly as well).

However, the existing implementation (via Library > Convert Photo to DNG) suffers from a few limitations:

• It is somewhat risky / confusing (if you do not choose the correct settings, you can lose data - such as flattening a TIF or using an older lossy format which does not offer the same small size and visually lossless results of the newer JXL format).
• It is cumbersome (requires multiple steps and more time than necessary).
• It does not allow you to import images to a drive with limited space (you need roughly 11x the working free space to import a standard image and compress it vs what you would need if the images were imported directly as lossy DNG).
• It is so hidden that few people will ever benefit.

All of those issues could be avoided if there were a simple checkbox to import images directly as lossy DNG. To be clear, the images should be processed consistent with these settings you would use via Library > Convert Photo to DNG:

• "Only convert RAW files" (do not flatten TIFs, etc)
• "Delete originals after successful conversion" (otherwise you won't save space)
• compatibility = "Camera Raw 16.0 and later" (use the new JXL compression for higher quality and smaller size)
• JPG preview = "medium size"
• "Embed Fast Load Data" should be checked
• "Use Lossy Compression" must be checked to get the size reduction.
• Do NOT "Embed Original Raw File" (otherwise you will not save any space).

This could be a checkbox labeled "convert to lossy DNG" under the "apply during import" section of the Lightroom Classic import dialog.

There are a few edge cases where lossy DNG should not be used (advanced demosaicing, etc). In addition, some users will likely never trust or want any level of lossy compression (totally understandable). Because of that, I recommend the following:

• The option should be disabled by default (ie the user must actively turn on any lossy option)
• A notice could optionally pop up when you activate lossy imports to provide information on potential caveats with this option (ie, such a warning may help alleviate any concerns about turning on the feature by accident or without sufficient understanding).

Such a system would enable significant benefit to many users by making it very easy to save a significant amount of file space with lossy (visually lossless) - while at the same time keeping the import behavior unchanged (truly lossless) unless the user consciously opts into the new option.

@adamapalmer , so I guess you would like an option to import as "Lossy DNG"?

I personally do not think that is a good idea, but if you feel strongly about it you can create an idea request and try to generate support for such a feature.

What do you love about lossy DNG (and the associated data loss)?