Not able to see improvement with HDR compatibility between Lightroom and Apple Photos

[sylwesterg95401861]

In a recent blog post about the newest updates to Lightroom, we can read:

>Embedded ISO HDR Gain Map support on export also means you no longer have to create two separate files for SDR and HDR. The HDR Gain Map will enable showing either the SDR or HDR rendition of your photo automatically based on display capabilities, ensuring a consistent viewing experience across devices. HDR Gain Maps are now supported in many apps such as Apple Photos, Google Chrome, and Instagram.

I quickly updated the Lightroom desktop to v. 8.0 to check it. I took one of the files I developed with the HDR effect and exported it to JPEG plus JPEGXL and AVIF with "HDR output" selected.

I don't see any difference. As in previous versions of Lightroom, AVIF and JPEGXL are HDR 10-bit images with no gain map. They look great* in Apple Photos on HDR displays but terrible otherwise. The JPG file does contain a gain map, but that happened after exporting from the previous version of Lightroom as well. Likewise, it is still not compatible with Apple Photos, despite what the blog post said: there, it always displays only an SDR base image. 

In other words, I struggle to understand what the "update" is about. Lightroom seems to behave exactly the same as before, I don't see any substantial changes in the exporting interface of HDR images, and images themselves seem to be equally (in)compatible with other software as before.

*Usually, sometimes there are artefacts after syncing through iCloud visible on other devices, but I suppose that is a bug in Apple's software.

[umlautnord]

I'm not entirely convinced, based on file size alone (comparing to Lightroom Classic exports using "maximize compatibility," which ensures a gain map is included), that Lightroom Desktop 8.0 is actually spitting out SDR + gain map images. That's what an ("HDR" JPG does).

If the default display of the image is HDR, or if it is HDR-only, it's going to look wonky in various situations depending on how it's tone mapped. Apple has gotten a lot better at tone mapping HDR-only images, so they don't look awful, but it isn't actually the "SDR version" if a gain map isn't being processed somehow.

It's possible that the standard uses HDR as a base minus gain map, but I'm unclear on that (again based on what Classic is doing), too. And again, file size makes me think there isn't a gain map included on what's coming out of Desktop 8.0. 

I may be wrong, but, I think there may be a little dust settling to happen here!

(Btw, I also have the Apple iCloud artifact issues with AVIFs/JXLs... my tip is to airdrop to an iPhone once you export out of Desktop. Don't import them on MacOS Photos.)

[sylwesterg95401861]

Hi, thanks for the comments. To be clear, I used Adobe's own "Gain map demo app," which they released as a demo tool a year or two ago. When you open any HDR file in it, it will actually tell you if it contains a gain map or is just a single HDR image.  I don't really use Classic, but Lightroom was adding a gain map automatically in JPEG exports if one first edits RAW in HDR. It was already working like that in the previous version.

This is why I'm confused about what changed and how this "improves" compatibility with Photos. Photos (on all platforms) still seem incapable of reading Lightroom-derived JPEGs with gain map correctly: will always show just SDR base in such files. As for AVIF and JPEGXLs, if one exports HDR-edited raw and selects "HDR output" during exports into that format, it just creates higher bit depth HDR files without a gain map. Those still look bad in macOS Photos because, for some reason, global tone mapper in Photos is not working correctly (other apps, like Preview or QuickLook, seem to render them ok).

Anyway, there are no gain maps in AVIF or JPEG XL; gain maps in JPEGs were there already, and if those are some "new" and "ISO HDR", at least with Photos, they (don't) work the same as previously.

[umlautnord]

Are you importing the JPG+gain map into Photos on MacOS? I have seen that it will strip the gain map no matter what. I always have to Airdrop it to my iPhone, where it's imported into Photos. Then, the gain map works in Photos on an iPhone, and renders base SDR on a standard Mac screen. That's the expected behavior; this is with the latest iOS. I do the same with pure HDR AVIFs to avoid artifacts. I don't understand why MacOS Photos is so grumpy about HDR, but, it's my workaround.

Yes—I agree that currently, I do not see Lightroom Desktop outputting anything other than the HDR-only files as it has before. No gain maps. I think this is a bug/issue/something. This is not the behavior that should be happening as described in the update notes. I haven't tested the iOS exports extensively to be totally sure what they're doing at this point, but the one test I did of an AVIF also seemed to be pure HDR. Which would also be a bug/issue.

I will say that I'm not sure the Gain Map Demo App is fully up to handling the latest standards even if the files are totally correct; it hasn't been updated since February. Seemingly unlike Desktop, Lightroom Classic is able to spit out SDR AVIFs with a gain map (which I can verify in Photos, using the same Airdrop method to avoid the gain map getting stripped). However, the demo app just says it's an SDR image without a gain map, which is incorrect.

I suspect that we'll need to wait for a bug fix for Desktop (and maybe iOS). Usual disclaimer that I'm not an authority on this, but, this is all to the best of my understanding 🙂

[sylwesterg95401861]

It works! The AVIF file with gain maps from LrC airdropped to the iPhone syncs correctly and is even displayed correctly on the SDR and HDR screens in the Desktop app. Thank you; this was making me mad!

EDIT: I was wrong, they still work incorrectly after sync, even if I airdrop them to iPhone. The only difference is that the files withe the new maps seem to display after syncing SDR version, so its not immediately obvious something is wrong. 

[umlautnord]

Not entirely sure what you mean—where is it displaying the proper SDR rendition, and where is it displaying in HDR? And what are the specific devices you're using?

[umlautnord]

Following up on what I said re AVIF + gain map / Gain Map Demo App—I hadn't updated to 17.0.1 at the time. It now properly recognizes the format, in my experience.

[Monstieur]

AirDrop to iOS no longer works with AVIF gain maps. When you first AirDrop the files, iOS 18.2 Photos displays the gain maps after a delay of about two seconds. Previously, the gain maps were displayed instantly. Then, after the files are uploaded to iCloud, the gain maps stop working completely as if you had imported the files on macOS. Once in a while, some photos might display the gain map after about ten seconds, but they usually never do.

There is a workaround where if you edit a photo on either iOS or macOS Photos using the magic wand or by making a trivial change, the gain map starts working instantly. On some photos, if you revert the edit, the gain map continues working, but on most photos you must keep a trivial edit for the gain map to work.

My previously imported photos using iOS 17 and Lightroom Classic 13 still have working gain maps that display instantly. I'm not sure if the issue is with Lightroom Classic 14 or iOS 18.

[umlautnord]

Hm. I'm seeing the delay of applying the AVIF gain map, but I also see that delay with other image types. Sometimes it is a gradual process of bringing the screen to the full dynamic range; here, it seems it's just a quick snap. That doesn't trouble me.

The rest of what you describe—losing the HDR display on iOS after the sync—is concerning. I haven't had that issue with iOS-imported (via AirDrop) AVIF + gain map images reverting to SDR-only, personally, when viewing in iOS Photos. Even after they sync over to MacOS Photos.

I'm on a MBP 14" M4, so MacOS Photos will display in HDR on the display. AVIF + gain map images that come in do require that weird "edit" step to be recognized there, though. (My favorite "edit" is just rotating it 360 degrees.) That's been a strange fix for Photos and HDR images/gain maps for a while now. Definitely pre-iOS 18, and not just AVIF + gain map. I've also run into it purely on iOS in the past, though I can't remember the exact details.

It's honestly hard to know exactly where the incompatibilities lie. Re previous images... I don't think that LrC 13 was able to export AVIFs with HDR gain maps, was it? I am pretty sure that was introduced in LrC v14. I also did have some issues with the LrC implementation of AVIF + gain map ("Maximize Compatibility") for a while... I haven't tested too much since then. Moved back to JPG + gain maps for the time being because of better tools to define SDR fallbacks.

I'll poke around a bit more with AVIF + HDR gain maps and see if I can discern anything.

[umlautnord]

Er - You've gotten better answers from Greg here: https://community.adobe.com/t5/lightroom-classic-discussions/hdr-lightroom-jpg-gain-map-support-avif...

[Monstieur]

Yeah, I'm using native HDR AVIF going forward. I don't really care about SDR.

[umlautnord]

Makes sense! Curious - do you still need to AirDrop to iOS, or can you get MacOS Photos to sync an HDR AVIF into the cloud and down to the iPhone without somehow ruining the HDR?

[Monstieur]

Native HDR AVIF works perfectly however they're transferred, including other apps storage apps as long as they're not transcoded.