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Question

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

Forum|Forum|1 year ago
January 4, 2025
3 replies
3221 views

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?

Windows

Seth A

Participating Frequently

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.

Y

yidal73355816

Participant

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

Community Expert

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

Community Expert

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.

D Fosse

Community Expert

@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.

B

bobknAuthor

Participant

.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.

D Fosse

Community Expert

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.

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.

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