How to compress raw files by 90%+ in Lightroom

[@fbottone]

I've been doing this for awhile - it works well. In Library module, you can select the Photo(s) you wish to convert, and hit Library->Convert Photo to DNG and it will do this in place for you. Check or uncheck "delete original raw" as necessary. I believe this also works on large TIF files as well.

[@migranthawker2952]

I set the Import dialog to automatically convert RAW to DNG every time I import images

[@gregbenzphotography]

@migranthawker2952 but as “lossy”? That’s the key to get this benefit.

[@BIGplanetLife]

I am always well pleased with all your tips and tricks. I purchased your Lumenzia, Exposure Blending and Dodging and Burning courses several years ago, having those plus these videos are an incredible value for any photographer that wishes to better their post processing skills. Thanks Greg!!

[@gregbenzphotography]

Glad you’re enjoying it all!

[@gregbenzphotography]

Glad you’re enjoying it all!

[@tomlitteral5738]

Thanks!

[@gregbenzphotography]

Thank you, Tom!

[@davidmccarthy3069]

Greg , this is a great overview of JPEG XL compression capabilities! Your comparison examples are really helpful.

[@gregbenzphotography]

Glad to hear it!

[@skiptaylor853]

@@gregbenzphotography Isn't this using the same JPEG XL compression that you now get when using the HDR merge function in Lightroom CC?

[@gregbenzphotography]

@skiptaylor853 that’s related technology, but used in a way that does not retain the RAW data. That approach is best reserved for files where you wouldn’t expect to do much further editing (though it’s much more flexible than JPG and can operate quite a bit if needed - it just isn’t as flexible as RAW).

[@anggaramahendra]

really helpful, thanks Greg😁

[@donncha1]

Hi Greg, I found your blog post first on this subject and hopefully, my blog sent a ping to yours from my post about it. One major thing to consider is that the Transform auto tool will "fix" them differently. Also, load the lossy and original into Photoshop as layers. Set the blend mode of the top one to "difference" and you'll see the minor differences in them. I think it's worth it TBH, especially for photos I might delete or not publish on my blog.

[@gregbenzphotography]

Thank you for the mention! You can definitely find differences if you look close enough, no question - I just haven't found anything significant enough that it would show in a print or any real use. Interesting comment on transform, I haven't used that much. That's surprising that such a macro tool would respond to such small changes.

[@cmichaelhaugh8517]

Interesting. But how do the compressed files process after doing the mosaic processes and then the compression?

[@gregbenzphotography]

DNG can either be mosaic (often RagGB sensor data) or in linear space (RGB). This uses the later, which is a partially processed but still RAW. Just like applying AI Denoise, shooting ProRAW with iPhone, etc. The processing is the same. As you see in the video, the settings carry over and the result is identical (aside from some minor compression artifact which is effectively undetectable).

[@J5388T]

Very useful video thanks Greg!

[@storiestellr]

I was unaware Lightroom now uses JPEG XL for lossy DNGs. This is excellent, thank you.

[@nookshorts1659]

Great video and very helpful, thank you!

[@rgarlinyc]

Very insightful, thanks Greg! I shall try this out on some of my candidate captures.

[@dataventurer9998]

One application benefit you didn't mention in your list of "When You Should Use Lossy DNG" - would be for real estate photos! They are a perfect use-case for conversion to DNG files because the photos are used for a limited time, are typically crunched by the MLS service then scraped by the real estate search sites, then ultimately viewed on a phone or desktop computer in less-than--full-screen size. The BIG benefit of conversion to DNG that I found was the increase in speed both while working in Lightroom, then a big difference transferring them to Photoshop and back for the flambient blending. A 16GB Windows 10 machine shows a huge difference in speed loading the layers, then saving a flattened file back into Lightroom. Since the original RAW files are typically deleted with just the final JPG files retained (and almost NEVER reused!), the storage angle benefit is not near as significant as the speed enhancement. I have been using the Adobe DNG Converter but your video here shows that there is almost the same level of control with the resulting file size using the Lightroom tools. The standalone converter offers more options in the Compression/Image Sizes. I tried a test with a dozen files (RAW, about 22MB each) both ways using the settings you showed and the "Limit Size to 2,560 Pixel Per Side" option in the standalone converter. The resulting file sizes were almost identical. Then I tried your recipe but didn't limit the long pixel side. Again, the file sizes were very close. I guess the decision to consider at this point is whether to import the RAW files into Lightroom and then convert them to Lossy DNG, or do the conversion with the standalone converter then import those into Lightroom. I did try to use the Enhance function to see what the AI Denoise process looks like - took WAY too long for a bulk real estate application. Bringing the nitty gritty details to our attention is very helpful! Thank you!

[@gregbenzphotography]

Yeah, probably any high volume work could really leverage this. A lot of event coverage would probably fall into that camp.

[@tomhofmann5277]

Brilliant! Thank you

[@dominiclester3232]

Excellent thanks!

[@onraj9mm]

nothing about editability? dynamic range? exposure? is it similar to the original file?

[@gregbenzphotography]

All same as original

[@neilatkinson3711]

HI Greg - I know I'm a bit late to the party here but just wanted to say thanks for this video. It's got me out of a hole. I've been using Rawsie for years, it's great. For some reason it doesn't convert any raw file from my new Sony A1 - the Rawsie people were helpful but as the product is no longer available they couldn't solve my issue. I'currently doing some tests but it now seems like after exporting my raw files as lossy compressed DNGs and re importing into LR I'm able to use the Denise tool even though the new DNG file says Mosaic Data - NO. can I just check that this is the case with you now. Also, one last thing. After exporting and creating Lossy DNG files they appear a very strangly when viewed as a thumbnail in my finder window, very dark and very green. Mac Studio. Have you any experience of this? Many thanks, Neil

[@gregbenzphotography]

I don’t typically browse these images either Finder, just LR. Sounds like a bug. I would submit a sample of the source and lossy compressed image to feedbackassistant.apple.com

[@ashenshugar4461]

Thanks, it was great.

[@harthamm]

Isn't this the same as using standalone Adobe dng converter? That seems to do a good job. Although with that I have lost metadata in the past.

[@gregbenzphotography]

I haven’t used that in a while, not sure if it has this. But the presence of lossy check and raw version 15.3 would pretty clearly indicate support

[@Axis23]

The compression is very good and saves a lot of disk space. Unfortunately the thumbnails of the created dngs cannot be viewed in Windows 11 Explorer. Thank you

[@gregbenzphotography]

Sure you chose the option to save a preview?

[@Axis23]

😮... I will try... Thanks

[@mikejohnston9113]

There don't seem to be a lot programs that can open this file format

[@gregbenzphotography]

Adobe software does, which means you’re in good shape unless you plan to switch to another RAW engine soon. Not surprising for a new DNG option. In the long run, anything which supports DNG will likely catch up.

[@shayrealestatephotography]

I wonder if the time used to create the new files and delete the originals (and all of the decisions therein) is equal in a dollar amount to the cost savings in storage. For me I doubt it's worth the extra workflow. I also wonder how well the new file can handle radical post processing changes in comparison to the original RAW? For instance, I know that a jpeg can look amazing on screen but falls apart quickly when making adjustments in post.

[@steveking6204]

Totally Agree!

[@gregbenzphotography]

JPG falls apart because it is not RAW and is 8-bit. These compressed RAWS are full quality. Zero chance you could tell if I used compressed or original in a print.

[@shayrealestatephotography]

@@gregbenzphotography Good to know, thanks.

[@echoauxgen]

Ok you can reduce to send to someone but then how does the other person bring back to normal size?

[@gregbenzphotography]

If you reduce resolution, that’s all they get. They could upsample, but that would not be same quality. I wouldn’t do that for print work. Just use lossy compression without changing pixel dimensions to send the smallest file that keeps full quality (about 4-6MB is typical for 46MP RAW).

[@Ancaja123]

Can you do this upon import?

[@gregbenzphotography]

I don’t believe so. There is a menu option to help convert in a batch though.

[@davidrussell9184]

Every file I save as a DNG in either Lightroom or Photoshop shows up with a Topaz Sharpen thumbnail. When I double-click to open them, they open in Topaz Sharpen. I cannot find where to turn this off. Any thoughts?

[@gregbenzphotography]

It probably set the default application for DNG to Topaz, just Google how to set the default app back to PS for Windows/MacOD. Or use the LR interface to open the images, no need to double click anything managed in LR.

[@madcrazy4photos]

How do you do this with HDR?

[@gregbenzphotography]

Exactly the same. It does not impact HDR support in any way.

[@mvermande]

Thank you for that Greg, I am curious though, you magnify your images at 1600% and they are still visible? If I do that, it's just pixels, and yet I start with a raw file from a D850, 45 MP. Why is this? 200% is about the most magnify I can go before it is too pixalated.

[@gregbenzphotography]

My RAW was similar resolution. I’m viewing on a 32” 6k monitor.

[@ericpecquerie4868]

With JPEG, when you open multiple time your original jpg image, the quality decreases rapidly. Do we have to expect the same with lossy DNG if we stay with Lightroom changes and t not pixel level changes done in Photoshop. Thanks for the answer.

[@davidshawe8982]

No, just opening a jpg doesn’t reduce quality. It’s only when you open, then make changes and resave multiple times.

[@gregbenzphotography]

This is a one-time loss of quality when you convert, and it is so minimal as to be visually undetectable. It won’t affect any real use. The risk would be potential inability to improve further at a later date (if some future software needs the original mosaic data). Note that this is JPEG XL, which is vastly better than JPG. The compression technology is totally different, even though the name is meant to be familiar.

[@ericpecquerie4868]

@@davidshawe8982 thank you, you are right. This is the problem I wanted to avoid by using DNG and PSD instead of jpeg. Now with lossy DNG I just wish to know how it evolves in time.

[@sumeetgudhka]

@gregbenzphotography, how much more processor-heavy is using this Compressed DNG over original Raw files. Do you have any metrics on that?

[@gregbenzphotography]

I don’t have any data, but see no impact. Normal work would use previews (proxies), so not likely a factor. JXL is pretty performant too.

[@rafo-graph]

really great tips!

[@Ancaja123]

WOW, as a Fujifilm GFX user, this is a lifesaver.

[@gregbenzphotography]

That’s great to hear. How big are those native RAW files?

[@Ancaja123]

@@gregbenzphotography Around 100mb even after converted to DNG.

[@gregbenzphotography]

@Ancaja123 that’s a monster. Bringing that down to 10MB or so? With AI noise reduction first will be smallest.

[@Ancaja123]

@@gregbenzphotography I just tried and it seems to bring it down to 20-30, which is still a huge difference. I'm not sure about using the Denoise feature as it's something I rarely use.

[@gregbenzphotography]

You can always use some other denoise later, so I wouldn’t sweat it. Thanks for the feedback, that’s quite a big image!

[@branchau]

You claim to see no difference viewing on a 32" monitor. I presume that may be a 32", 2K monitor. What would it be like on a 32", 4 K monitor?

[@gregbenzphotography]

There is no meaningful difference, I was just stating that I have been reviewing these images in close detail (beyond anything useful for print).

[@LightAndColorPhoto]

Greg, this It's a much too general statement... the fact that YOU don't see any difference is not an argument that the photo was not affected. It is against logic to claim that removing information from the file has no effect on the image level (color, shade, brightness, interaction between color shades on contact, etc.). Do not forget the fact that not all people see the same number of color shades or we do not all see the same colors - Abnormal trichromacy (the three cones are sensitive to a different wavelength). The fact that you find it advantageous to save space on the storage medium, at today's prices for SSDs (or any other storage method) for me does not have enough weight to make me give up the information I captured in the original photo. My two cents...

[@gregbenzphotography]

Try making a very large print with both the normal and compressed RAW and see if anyone can spot a difference. I think that’s extremely unlikely.