Photoshop 26.2.0, Windows 11 24H2, ansd automatic color management

[bobkn]

I've found that when running Photoshop CC 26.2.0 under Windows 11 24H2 (build 26100.2605), it iappears to be necessary to have automatic color management enabled for PS to run in 30 bit color mode.

(Graphics card is an RTX 4090 set to 10 bit color. Latest nVidia studio drivers. The monitor is a Philps 27E1N8900 OLED. which is 10 bit capable.)

PS can be set to display in a wider gamut than sRGB.

Is there an explanation?

[D Fosse]

@bobkn 

1 - there is no such thing as "enabling automatic color management" in Photoshop. Color management is always running. The question is just whether there is an embedded document profile and a valid monitor profile.

2 - color management and bit depth are two different things unrelated to each other. One does not affect the other.

3 - 10 bit output needs to be enabled in the Nvidia driver. As far as I know it's only available with the Studio driver, it is not available with the Game Ready driver. You also need to connect the monitor by DisplayPort. Once enabled in the driver, it can be set in Photoshop Preferences > Performance.

4 - it is very easy to confirm whether the display really is running at 10 bit per channel depth (30 bit). Just make a gradient in Photoshop, in a 16 bit document. Almost any gradient will do. If you see any banding there, any stepping between values, you do not have a 10 display pipeline. True 10 bit display is perfectly smooth in every possible instance.

[bobkn]

.1. Correct. I meant enabling ACM in Windows. There is no such setting in Photoshop.

2. Also correct, as far as I know.

3. Incorrect, probably just out-of-date. Recent Game Ready drivers also support 10 bit. I use DisplayPort cabling, but I believe that HDMI 2.0 and up also supports 10 bit, but I don't use HDMI.

4. Already doing that.

There are some odd things going on, at least from my point of view. If the nVidia control panel is switched from 10 bit to 8 bit, ACM is disabled. (It can be enabled again in the Window settings.) Going from 8 bit to 10 bit enables ACM.

It appears that ACM must be enabled for Photoshop to display in 30 bit color.

It appears that Photoshop will also give a step-free display when it is set in 30 bit color, ACM is enabled, and the graphics drivers are set to 8 bit color. I suppose that PS dithers the image to emulate 10 bits.

Web searching found no documentation of this. I even tried Microsoft Pilot, which returned hallucinations and irrelevancies.

[bobkn]

I should have added a disclaimer: this is what I observe on my own PC. I can't claim that is typical behavior for Windows or Photoshop.

The toggling of ACM based on switching bit depth in the nVidia control panel has been seen by others, so it may be "normal".

Per Item 3 above, I am using the Studio drivers, even though I doubt that it matters much.

[D Fosse]

I've had 30 bit enabled for my Eizos, on two different systems (Win 10 and 11), for many many years, and it has always worked 100% reliably. No special settings other than enabling it in the Nvidia driver and in Photoshop.

In a standard scenario, Windows isn't supposed to do any color management. Photoshop converts into the monitor profile and those corrected numbers are sent to the display. The emergence of HDR displays has changed the rules quite a bit. I know there is a setting for "accurate color management" in Windows when you have HDR enabled. Is that what you're referring to?

[bobkn]

As far as I know, there is no "accurate color management" setting. The one I refer to is "automatic color management".

I had  no struggles with it in Windows prior to Windows 11 24H2, which started to be released in the US in early October, 2024. I've found that ACM messes with monitor profiling software (Calibrite Profiler, DisplayCal/Argyll CMS). Some makers of monitors for professional photo work have proprietary software that is modified X-Rite software. That may not produce a wide gamut profile, so ACM would have to be disabled. (Or the compatibility setting for the app to use legacy color management may work.)

HDR is something entirely different. It's a separate mode in Windows. There is a switch for it in Display settings. Some applications can switch to it automatically, and switch back when the app is closed. I rarely use HDR; I'm not sure that it's recommended now for photo work.

SDR mode supports 10 bit color (30 bit in Photoshop). I've used 10 bit SDR is PS for a long time.

[D Fosse]

OK. I haven't updated Windows 11 to 24H2 yet. I'll check around before I do and post back if I find anything.

(I use Eizo Colornavigator, and Eizo are usually on top of any issues with new operating systems).

EDIT - out of curiosity, what is the default setting for this switch in 24H2?

[Erik Bloodaxe]

My Windows 11 System updated itself to 24H2 without my realising. I found that profiling software was no longer functioning as it used to eg. monitor profiles could no longer be saved or applied. I took a while to figure out why but it was because Windows ACM was turned on by default and had altered my color settings in NVIDIA Control Panel. I couldn't even turn off ACM before returning these settings to my normal values without my monitors turning bright pink! Confessing my ignorance, I new nothing about ACM before this happened but, now that I am aware, I ensure that it remains firmly off.

The default therefore seems to be ON.

[D Fosse]

I have since updated to 24H2, and didn't have any problems. Monitor profiles load correctly, and 10 bit display works. ACM is on.

It doesn't look to me like there's an inherent problem anywhere here, it just may need to be reset after the update to work correctly (but it wasn't necessary here).

[bobkn]

The issue I had was with monitor profiling software (Calibrite Profiler, DisaplayCal/Argyll CMS). Under 24H2, with ACM enabled, the monitor was profiled to sRGB.

That can be avoided by diabling ACM. Profiler also works properly with its compatibility set to "Use legacy ICC color management". For DisplayCal, I disable ACM.

A previously generated profile works OK with ACM enabled.

It appears to be necessary to have ACM enabled to get 30 bit color in Photoshop.

I hope that Microsoft and the thrid party vendors get this sorted sooner.

[Erik Bloodaxe]

I use Datacolor Spyder X2 for monitor profiling. The software is unable to save profiles or apply previously generated profiles when ACM is enabled. The manufacturer's advice is to keep ACM disabled.

[D Fosse]

This has to be a bug in the Datacolor software.

Again, all my custom monitor profiles work correctly, and I didn't need to do anything at all after updating to 24H2. Everything works just like it always has.

[D Fosse]

Hang on. This is odd. I took a closer look in Windows settings, and it turns out there is no checkbox for "automatic color management" at all. From other screenshots I've seen, it should be here:

Yes, this is Windows 11 24H2, updated about a week ago.

Could this be tied to HDR-capable displays? Mine isn't.

Or could it be that this is actually not about the monitor profile, but the calibration tables? It wouldn't be the first time that distinction is misunderstood even by people who should know better. The Eizo I'm using has hardware calibration, meaning the calibration tables are not loaded in the video card, but internally in the monitor. None of this affects how the monitor profile is used, but the OS/GPU doesn't need to load the calibration at startup.

Here's the Color Management tab:

I actually have 4 monitor profiles that I switch between, but Eizo Colornavigator loads them into the OS as needed, so that only one is visible in Windows at a time. The point is that I've tested all these profiles and they all load correctly.

[Erik Bloodaxe]

Curious!

My analogous system settings look like this:

The switch for "Automatically manage colour for apps" is often shown in a different place in other screenshots.

Descriptions frequently say it is found under System>Display>Advanced Display which is where you were looking. In my case, it never was there - in fact it wasn't anywhere until 24H2 was installed and now it appears as in my screenshot.

What is your OS Build? Mine is 26100.3037

[D Fosse]

@Erik Bloodaxe I'll have to get back to you with OS build, I'm on a different Win 10 machine right now.

But this is really odd <scratches head>. Why do some get it and others not? And if not, does that mean it's on or off?

Have you ever opened or used the built in Windows calibration tool? ( I haven't). Just wondering if that could trigger it.

[Erik Bloodaxe]

No, I have never looked at the built in Windows caibration tool. Only ever used third party hardware and software, Datacolor in my case.

Oh, and in response to your asking, "Could this be tied to HDR-capable displays? Mine isn't.", well, mine are not either.

Something else of concern about ACM that I have noticed is that, if enabled, NVIDIA colour settings are immediately changed so that Desktop colour depth is set to SDR (64-bit). Disabling ACM does not reset this which seems to be the reason that my dispays turned pink and distorted when I simply switched off ACM. I am forced to change colour depth back to SDR(24-bit colour) manually to restore normal service.

Came upon this from NVIDIA Support which explains (or confuses us) more. Datacolor say disable ACM but NVIDIA say keep it on!

[D Fosse]

OS build 26100.2894. Says it's up to date, but slightly behind yours.

I'm not getting those Nvidia settings either (RTX 3060), which are apparently post-ACM. Mine still says 32-bit for desktop color depth, which I would normally interpret as 8 bit + transparency effects.

Under output I have 10 bpc, which works in Photoshop - that's easy to test with a gradient.

I can't figure this out. At this point I think I'll just wait for further updates and see how it plays out. After all, there's nothing here that causes any problems for me so far.

[yidal73355816]

ACM was pushed out differently deending on your hardware. I have been on Windows preview build for 2 years and  I was supposed to  have this "ACM switch" 1 year ago according to the  build number but I just  received the update this week. 

If you don't have it, it's your luck. It only makes color management worse.

[yidal73355816]

The  advice is to disable ACM and allow Adobe and other professional software to handle color accurately just like they'have been doing for last 20 years.

The ACM is still broken and there is a wide range of weird issues with it.

The explanation here applies to  SDR only. With  HDR on it's more confusing.

Basically the idea of ACM is, any legacy (non windows UI app) are considered to only run in sRGB mode and they always deem your display as a sRGB narrow gamut display. The biggest issue with this is, there are quite many apps including Photoshop that knows how to handle wide gamut for decades and now they lose the capability. Even Chrome and Edge have been doing this well that all contents (including the UI) are not oversaturated and are converted accordingly per your display profile. They have been able  to show wide  gamut contents (P3, AdobeRGB, proPhoto) correctly before ACM. But now with ACM they are fully restricted to sRGB. Check "wide Gamut test" pages for yourself.

And Photoshop, as a legacy app, will be wide-gamut blind after enabling ACM. One workaround is to check "use lecacy ICC " in the app setting. It will override ACM (so you notice the banners  and UI elements are oversatureated again with ACM). But I am pretty sure the color conversion is done wrong in this way.  Pictures become washed away and less saturated than they should be. It looks like the color conversion is done "twice"!  Everything appeared wrong in this case.

The last thing is, we don't know under ACM if Windows handled the conversion correctly. Ideally it should use your stored ICC profile that has the measured XYZ coordinates to force everything from display native gamut to sRGB, right? But it might have used the EDID instead, which are factory preset XYZ coordinates that are never accurate. 

Windows have been disastrous on color management. They thought they are clever by introducing ACM but instead they just created another more sophisticated CRXP .

[NB, colourmanagement]

Wow, some gtreatv inside in here from, you all but how confusing. Its not even easy to know where to go to switch it off!

neilB 

colourmanagement 

[D Fosse]

If you don't have the switch, it's off and you won't have any problems. Everything works as it always has.

If you have the switch, turn it off. Ditto, you won't have any problems.

What's confusing is why some have it and some don't. But the purpose is apparently to aid with applications that don't support color management. That's really not a critical concern.

Just leave it off.

[NB, colourmanagement]

@D Fosse "What's confusing is why some have it and some don't. But the purpose is apparently to aid with applications that don't support color management. That's really not a critical concern.

Just leave it off."

It could perehaps actually help a lot on non colourmanaged apps for users with wide gamut displays, I guess.

The fact that it apparently messes with Photoshop rather negates that advantage, though.

Is it always in the same place in Windows (if present) please?

And always under the same name? 

Posts (screenshots) above seem to suggest otherwise, but maybe I misunderstood. 

thanks

neil barstow colourmanagement - adobe forum volunteer,

colourmanagement consultant & co-author of 'getting colour right'

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[Seth A]

Having the same issue, the only way to have 30bit enabled in photoshop ( and working )  is only with ACM on. 

Also windows color management is not changing ICC profiles anymore. If you check/uncheck the "use my settings for this device" will not make any profle change. The only option that works is the legacy compatibility on each app, which of course is not a solution. This is by far one of the worst bug in Microsoft for Professional Designers/Photographers/Visual Artists.