Technical monitor colour mystery

[SirFido]

Hiya guys!

Just bought a fancy new 4k 10-bit monitor and was playing around with the NVIDIA control panel and Photoshop to see whats up.

However, I noticed something strange that I can't wrap my head around. Changing from 8-bit to 10-bit output in the control panel does not seem to do anything?

 

Among many tests I did, I created a gradient from blue to red in Photoshop with 16-bit per channel enabled. Theoretically, this gradient should have more banding when I turn the monitor to 8-bit in the NVIDIA control panel. But it doesn't. It looks completely the same. The same happens in lightroom. And if I export to a 16-bit tiff and view it in the normal photo viewer. The same happens with different colour management profiles enabled (not that that should make any difference).

I know my displayport cable is capable of carrying a 4k 10-bit signal. I've tried different colours at different saturation levels. There is always a little banding of course, but there is no difference between 8-bit and 10-bit.

 

Output colour format is set to RGB and dynamic range is set to FULL.

 

I've got this monitor: https://www.lg.com/us/monitors/lg-27gn950-b-gaming-monitor

 

Have I just misunderstood something about 10-bit, or am i missing some piece of the puzzle? Is there some setting somewhere I don't know about?

I should see more banding when viewing a 16-bit per channel gradient up close on an 8-bit monitor as compared to a 10-bit monitor?

[Stahlmann]

It's not a native 10 bit panel. It's an 8 bit panel that uses dithering (FRC) to emulate 10 bit.

If you set it to 8 bit in your driver settings, it'll do 8 bit and your GPU will apply dithering, so it's basically 8 bit + FRC.

If you set it to 10 bit, the monitor will do the dithering and you'll get 8 bit + FRC.

 

Keep in mind that this isn't necessarily a bad thing. 8 bit + FRC can look as good or better than native 10 bit without dithering. The results still varies from each monitor to the next.

 

For example my LG C2 is a real native 10 bit panel. Still, gradient handling is superior when i use it at 8 bit + FRC.

[Glenwing]

Back in the day at least, GeForce cards did not support 10 bpc color depth in OpenGL applications like Photoshop or other content creation software; this was restricted to Quadro cards. I don't know if this is still true though.

[e22big]

Honestly... I think 16 bit banding is just a myth. There are people who try really hard to find banding issue when editing photo in Lightroom and from what I know - there's basically no different from 10 to 16 bit.

 

I shoot regularly in 12 bit RAW as well and just never saw any banding whether on 8 or 10 bit display. The added colour space is way more useful to me than the colour bit rate

[Kilrah]

99% of the content you watch on a monitor doesn't have visible banding even on 8-bit - there's a reason this has been the standard for so long, it's good enough in most cases.

 

To make it visible you're going to have to specifically create an image that is challenging, usually really dark and monochromatic, a nice bright image with vivid colors isn't going to show much. 

 

In most cases when you see banding it's not even due to the display, it's because someone did something silly to the source material and it's baked in there.