SqueezeGuide · Compatibility
JPEG XL DNGs in Lightroom: what they are and who can open them
A JPEG XL DNG is a DNG 1.7 file that stores its image data with JPEG XL. Lightroom reads it. Many other apps either do not, or we have not checked them. Here is what we tested, what we did not, and the older format for wider support.
What a JPEG XL DNG is
DNG is Adobe's open RAW format. Version 1.7 of the spec lets the image data be stored with JPEG XL, a modern image codec. Our files hold 16-bit linear data inside a standard DNG 1.7 file. The Balanced setting uses JPEG XL distance 1.0.
In our test on one of Ferdi's Fuji X-T5 files, a JPEG XL DNG came out about 85% smaller than the RAF on the Balanced setting.
Who can open it
The table shows what we tested and what our notes say. Anything not marked Tested or Owner tested is unverified, so test it first.
| App | Status | Notes |
|---|---|---|
| Lightroom Classic 15.x | Tested | Full raw controls in our tests. |
| Adobe Camera Raw | Tested | Full raw controls. Our notes say version 16 or newer. |
| Lightroom Classic 13 and newer | Not verified yet | Not re-tested. Our notes list it, not verified. |
| Lightroom (cloud) | Not verified yet | Not re-tested. Our notes list it, not verified. |
| Photoshop 25 and newer | Not verified yet | Not re-tested. Our notes list it, not verified. |
| Bridge | Not verified yet | Not re-tested. Our notes list it, not verified. |
| macOS Finder, Quick Look, Preview, Photos | Owner tested | Show the Mac & Lightroom format at full size. The mosaic format shows black. |
| Capture One | Uncertain | Treat as no until tested. |
| DxO PureRAW and PhotoLab | Assumed no | Not tested. We assume they will not open lossy DNGs. |
| Fuji X RAW Studio | Assumed no | Needs the camera and the original RAF. Not tested. |
| Photo Mechanic, FastRawViewer | Not checked | Unverified. |
| Windows Explorer thumbnails | Assumed no | Not checked. |
| Lightroom older than 13 | Assumed no | Not checked. |
The Mac thumbnail trap
Finder uses a small embedded preview, 1024 px, for quick views. Anything larger has to decode the real image data. In the Mac & Lightroom format that works, and Finder, Quick Look, Preview and Photos show the full image. In the mosaic format, those same apps show black at full size. Lightroom reads both.
The older format for wider support
If you need a lossy DNG that most raw programs can open, use the Classic format. Squeeze calls it "Classic (max compatibility)". It is a DNG 1.4 file with lossy JPEG inside, a standard from 2012, and it stores 8-bit data.
Our app notes say Lightroom 4 and newer, and most raw apps, should read the Classic format. Capture One, FastRawViewer and Photo Mechanic should work, but we have not tested them.
The Classic files are about 3 times bigger than the Mac & Lightroom files. Do not expect DxO or Fuji X RAW Studio to open Classic files either. To switch formats, open Settings, then Advanced, then Format, and pick Classic (max compatibility).
What we have not checked
- Capture One. Our notes say its support for JPEG XL inside DNG is uncertain.
- Photo Mechanic and FastRawViewer. We have not verified either one with the JPEG XL format.
- Lightroom cloud, Photoshop and Bridge. Our notes list them as opening the files. We have not re-tested each version.
- Windows. We assume Windows Explorer thumbnails will not show the files.
- The Classic format in each app. We have not tested each one, so test before you promise a client that a file will open.
Is the format future-proof?
The format is open. DNG 1.7 is an open Adobe spec, and libjxl, the JPEG XL library, is open source, so the files should stay readable. The number of programs that read JPEG XL inside DNG is still small, though. Keep your originals until more apps catch up.
What to do
- Check the apps you use against the table above.
- If an app you rely on is uncertain, test one file in it before you convert a batch.
- If you need the widest support, use the Classic format and accept the bigger files.
- Do not send a lossy DNG to DxO or Fuji X RAW Studio. We assume they will not open it.
Quality is a separate question, and our lossy DNG guide covers it. Get Squeeze at squeeze.photos/#install.