Had my monitor replaced recently by Dell with a new U2518D that supports HDR. Problem is that when I enable HDR in Windows 10, the brightness continually fluctuates to dim then bright then dim every 2 minutes. Happens also when watching movies and videos with HDR enabled software. Once I disable HDR in Windows back to SDR there is no problem.
I've connected the U2518D to PC via High Speed HDMI 2.0 cable. Enabled HDR on the U2518D Monitor (Smart HDR on) and set Windows 10. Display setting HDR and WCG to ON. Also have the default U2518D Color Profile D6500 installed.
OS is Windows 10 1803 with all the latest updates installed and video card is Nvidia GTX 1070. Had a look though the forum and noticed this post having similar issue with HDR enabled.
When on the Windows 10 desktop, using applications like YouTube, Yahoo mail, Google Chrome browser, Office, you must turn HDR OFF. Do this and tell me if the dim/bright/dim still happens.
As I already mentioned in my first post when I turn off HDR setting in windows everything is fine no continually going bright then dim then bright every two minutes. Its just when I trun on HDR screen will continually go dim/bright/dime etc.
Your suggestion is only turn on HDR when watching a video/movie or playing a game that supports HDR. Ignore the constant changing brignthes an just watch/play everything in full screen. Not in a smaller window.
HDR movie and HDR games are designed to be used in full screen. By shrinking the HDR content to a smaller window, you are trying to use the HDR content and the non-HDR windows desktop and non-HDR applications simultaneously. You cannot mix the two contrary technologies. It is either;
* HDR off, use non-HDR windows desktop and non-HDR applications
* HDR on, use HDR movie or HDR game in full screen
Definitely something wrong when I enable HDR in Windows 10 1803. As I said when in my first post the display contrast constantly fades from bright and vibrant to dark and washed out then back to bright again every two minutes. Even when HDR is enabled and detected when playing back the video in full screen mode.
When I turn HDR off the screen is perfect in SDR mode.
Not sure if the constantly changing contrast problem when HDR is enabled lies with the monitor, default Color Management ICC profile, video card settings or Windows itself?