What is causing this HDR artifacting and how can I eliminate it?

Question

When I turn HDR on in Windows 10 there's some strange artifacting and I'd like to understand what's responsible for it.

Here's a sample smartphone image taken of the Edge browser maximize window icon with HDR disabled:

And the same image with HDR on:

Notice the grey pixels immediately to the left and right of black pixels are now white (but not above and below) Why? Is this introduced by windows, my graphics card, my monitor?

HDR looks great on videos but text and the Windows UI is made to look much worse. What should I investigate here? Is there any way to have Windows enable HDR automatically but only for full screen video?

My system specs:

• NVIDIA GTX 1060, driver v460.89 (latest)
• Windows 10 build 19042 BenQ
• EW3280U monitor

Answer 1

This may come across a tad cynical…

"HDR" on a single exposure image without a wide input profile such as P3 or ProRes is little more than a consumer con. It's an over-emphasised contrast pushing to a screen that really has no true input information (& usually no accurate profiling at all).
It's a fad, a marketing ploy, a selling point.
What you are seeing is the result on what was a crisp image, now with added consumer overkill.
HDRi is nothing more than a guess.

Sorry.

BenQ's own admission they're making it all up - https://www.benq.eu/en-uk/knowledge-center/knowledge/how-hdri-increase-immersion.html

Answer 2

This occurs because the monitor is not actually displaying more dynamic-range but it applies a filter to increase edge contrast. By making the immediate pixels brighter, there is greater contrast between them which is what it wants you to perceive.

The filter must be applied on scan-lines before it is easier than doing it across rows which is why it makes the pixels on either sides brighter but not those above and below. Essentially, it is trickery to create the perception of HDR without having a wider range of brightness available.