Black level

I have a pair of 27" monitors on my Windows 10 desktop. They're AOC model E2752. I have a completely black desktop, no background image.

I noticed that the "black" is not really black. It just dark gray. I presumed that these must be cheap monitors, lacking the ultra-black capability of better monitors.
But no! I opened the Nvidia control panel (I have an Nvidia 1060 card) and starting messing around. I found this:


Notice the "Digital Vibrance" setting. It's at 50% for this monitor (and likewise for the other one).
I changed it a smidge ... up to 51% ... and the black background became as black as coal. Nice.
I moved the control further up and down, with no change. (It does change the color intensity as I go extremely high or low, but never mind that.)

I moved it back to 50% and the background remains nicely black ... for a while.
Eventually it returns to its former dark gray ... at which time I can once again jog the digital vibrance up or down, and get the nice deep black once again.
I have not yet noticed what triggers the return-to-gray.
Maybe after a sleep-wake cycle?
Maybe after running some program?
Maybe when the squirrels are running around in the back yard?

I just don't know. But I do know this: I want my proper, totally black background to "stick". I don't know why it won't, and I don't know the cause.

Thanks. I made that change ... and I'm still dark gray.

You are going on about black level but actually using controls that don't directly affect this.

Nvidia has their own way of describing things, "Digital vibrance" rather than colour saturation etc.

By increasing the colour saturation the nominal black colour is below the black level of the monitor thus actually cutting off.

It is a matter of personal opinion, but I always prefer a very dark gray to pitch black knowing that nothing a very dark gray colour is being cutoff.

I see your monitor has DCR dynamic contrast ratio which will also affect this. Not to mention "viewing styles" as well.

I would fix on one "viewing style" and switch off DCR so that there is no autoing, and reduces the amount of variables.

I found the Color Management screen, and it shows this:

That's for display 1. And for display 2 it's the same.

It references file 2752H.icm ... so I searched C: for that file. Not found. Maybe that's a problem?

I searched on AOC's web site, hoping to find that file for download ... but those guys are worthless. No manuals, no support, nothing.
Anyway ... I don't know what I would do even if I could obtain a copy of 2752H.icm

As for the DCR thing ... I'll have to go back and look for that setting (and turn it off) later today.

Your ICC profile is OK, it is installed for your monitors.
No problem with that. To actually use it you would select it and Set as Default Profile.

You will find the ICM files in C:\Windows\System32\spool\drivers\color

Windows updates has already downloaded and installed it when you first connected up your monitors, whilst you were not looking...

Similar models listed on the AOC website, though cannot find an exact match, they vary models with countries but you don't need that it's been done.
http://www.aocmonitorap.com/sg/download_driver.php

DCR is off, and always has been.

Right now the screens are black, as they should be. Not sure whether that will last long.

One monitor is back to gray again. The other is black.

Any other idea, guys?