Nvidia Dithering

If someone gets eyestrain from reading black text on white background then it should hint that the problem is not with dithering, right? Because any screen can show black and white without dithering.

JTL Does the pattern occur even on white background? It's hard to see from the video.

pocupine White isn't really white, I assumed everyone knew that but perhaps not. Black text on a white background means that you've got massive amounts of FRC happening, might as well be a beige or purple background at that point. All three subpixels are firing to make white. Also "white" is a relative term, depending on gamma, color profiles, etc. so the assumption that there's no dithering with a white pixel is ... 100% incorrect.

pocupine Let me clarify:

1. You aren't ever going to get #ffffff, it might seem like you ought to be able to, but you aren't. Even if that's what you specify, it's not what you'll get. Color profiles futz with that. Now, it might be a reasonable supposition that if you SPECIFY #ffffff, then the card shouldn't dither, right? But you'll find in many cards there is simply no way to turn off the FRC. And FRC isn't selective... often it's applied as a final stage filter (although not always), after all other modifications (including color profile) have been applied.

2. You would be correct IF a card ever output #000000 or #FFFFFF, that the monitor at that point should NOT dither it. But again - many do. Plasma TV's, as an example, can be told to display pure black or pure white, and will instead do a rolling color output. Partly this is power saving, partly it's to prevent image retention, partly it's to squeeeeeeeze more colors out of the device than it can actually produce.

3. Many devices screw with the final output color, even if that color is white or black, based on the adjustments of the device. Long gone are the days when you can say "display pure black" and have the monitor simply NOT LIGHT those pixels... and rely on the backlight for lighting adjustments.

So while I agree with you in principle, I think that in practice the ability to say "it's pure white, it's DEFINITELY NEVER DITHERED" is limited.

pocupine Well if you run f.lux it wouldn't.

What about this? (As an example)

http://creativebits.org/mac_os_x/windows_vs_mac_monitor_gamma

pocupine You don't need sources. Set your background to white, then go into the control panel for your video card and yank on a slider and watch the screen output change... this is 100% the case for every video card. There is a software or hardware layer doing various fuckeries with the output before it goes to the monitor. I agree with you that IF you really sent #FFFFFF to the monitor it SHOULD display it without dither (although the monitor has software that does other fuckeries). But good luck making that happen.

Do you think Windows 10 introduced dithering and that's why a lot of people are having trouble with it, even on monitors that are using 8-bits per pixel?

Do you have any suggestion on how I can test if my eyestrain is due to dithering?

Why not try contacting NVIDIA through official channels and ask them about dithering on 9xx/10xx cards? DevTalk and other forums aren't going to get us anywhere. and @si_edgey for starters put the Temporal Dithering discussion on the NVIDIA forum in the wrong category, for starters.

https://nvidia.custhelp.com/app/ask

If enough people contact them, maybe they will notice.

I have been speaking to Nvidia and was escalated to a member of the driver team. He has not promised anything but has submitted a feature enhancement request to try and have dithering options included in future drivers. I have written back to try to get clarification of what has changed in the 10xx series hardware (and also later 9xx cards potentially) so will report back.

He was actually very compassionate about the issue and (as expected) had never heard of this being an issue before. I would recommend that everyone get in touch with Nvidia to start making a noise about it so they are more likely to listen!

si_edgey Good luck

JTL I have attached my resposne

Hi Derek

The problem with the developer forums as others have noted is that NVIDIA employees don't really read the forum, let alone the ones responsible for driver and/or VBIOS development.

It would be interesting to see if temporal dithering is enabled in hardware with the later 900 and 1000-series cards. I am running Linux which does allow you to disable dithering in the driver yet I notice with a high speed camera what appears to be dithering with a BenQ 8-bit VA panel monitor over DVI (tested with EVGA GTX 1070) and as others have noted it can cause some eyestrain and headaches that are absent without the dithering.

I appreciate your help though.

Here is his response

Sorry I couldn't be more help. Passing on this sort of user feedback is all I can really do.

Derek-

Batou @Slacor How does it look with 750Ti?