P: Mac M1 Mini Can't use 30 bit on Photoshop 2021 or 2022, but 2021 works.

Even though I have this 10-bit test on my Mac, I tried downloading it from Dropbox to make sure nothing funny happened to it (like maybe somehow I uploaded a JPEG etc). Well, it looks as expected on my SpectraView in the latest version of PS on macOS 13.0.1 at 100% zoom. 

The 30-bit check box is grayed out, and more importantly, there's a check mark. 

Thanks for all of the informative updates.

The BenQ is connected via USB-C male-to-male connector directly from the back of the Mac Mini itself.

Using the HDMI on a Mac Mini produces something ... awful. Makes everything look oversharpened and not good. I use the HDMI for a second monitor--a Dell U2713H. In any case, the BenQ is not hooked up via HDMI.

The chain involved in the USB-C / Displayport path is literally USB-C connector directly on the back of the Mini, though a several foot usb-c cable, Thunderbolt 3 acceptable, and into the USB-C port on the BenQ monitor. So, I think we can safely eliminate lower bandwidth portions of the path.

The comment about checked and grayed out was interesting. I'd be happy with that, but to be paranoid I confirmed that in PS23, it is still grayed out and not checked.

I have looked at 10 bit images or at least what I had reason to believe were, previously, and they looked smooth. I'm actually puzzled why that specific sample image looked bad. Maybe it is just an odd path in the code behind the checkbox, and that the data path is a clean 10-bit? I wouldn't deny, but the grayed out box is puzzling. Also given that an old release of PS shows it as 10 bit, tends to support a 10-bit per channel data path.

In any case, I appreciate all of the support here. At this point I'm reasonably sure the data path is 10-bit per channel, and that PS is mostly behaving that way, this one recent example seeming to be an exception. In any case, it doesn't seem to be anything simple or with an obvious workaround, so I'll just proceed with what I have. And again, I really appreciate all of the input, suggestions, and help.

Dave

Hello, according to https://www.benq.eu/en-uk/monitor/photographer/sw270c/specifications.html this display is supposed to support billion of colors, usually the 10 bits per channel.

Marketing rubbish, but all the display manufacturers make similar claims (no, they do not support or produce billions of colors, they might produce billions of device values* and that's a huge difference). Ditto for scanners or anything else making such a claim. 

Yes, that panel may very well be high bit. But again, the entire video path has to support high bit, including the OS and the software. That is doable. And again, the 30-bit check box should show us that being the case. So why the test image shows banding is something worth looking into. Of course it has to be viewed at 100% (1:1). And again, on my system, it is utterly smooth everywhere. Yes, it is possible that the cabling used from (Mac?) to display is an issue. 

* http://digitaldog.net/files/ColorNumbersColorGamut.pdf

The M1 mini has HDMI and two USB-C/Thunderbolt 4 ports. Sounds like you'd need either a Thunderbolt display or DisplayPort over USB-C.

Hello, according to https://www.benq.eu/en-uk/monitor/photographer/sw270c/specifications.html this display is supposed to support billion of colors, usually the 10 bits per channel. and it is listed as supporting HDR10.

According to Eizo, DisplayPort or USB-C, both will work: https://www.eizoglobal.com/support/compatibility/gpu/10-bit-photoshop18orlater-mac/index.html 

You can't use HDMI, it doesn't have the necessary bandwidth.

The 30 bit checkbox in Photoshop just means that PS is outputting 30 bit data. It doesn't know about the rest of the chain (GPU > interface > display panel), it all has to support it.

You don't need a 30-bit display but one with more than 8-bits per color in the panel and the rest of the video path. But it sounds like you so if the PS checkbox is on/grayed out. So not sure why you're see banding on the test document (I see none).

I'm using DisplayPort on a SpectraView.

I have an M1 mini and that 30-bit box is checked and greyed out. I do not have a 30-bit display. How are you connecting- USB-C or HDMI?

I opened the image "10 bit test ramp.psd" from dropbox, and it has distinct steps. PS says that the image is RGB 16 bit.

Then you don't really have a full, high bit display path or it would be smooth. Yes, the display matters too. Many are not high bit (some are not even 8-bits per color).

Yes, that test image is in 16-bit. 

I opened the image "10 bit test ramp.psd" from dropbox, and it has distinct steps. PS says that the image is RGB 16 bit.

However, if I open an RGB 16 bit or 32 bit image and drag a gradient across the image, it looks quite smooth. Certainly no distinct steps.

By the way, does it matter what monitor I'm using? I have a BenQ 270C.

Thanks for all of the help here.

Dave