I just purchased two LG 27UK550-W monitors and noticed that when I dim the monitor (using Night Light or Flux) I get a very noticeable halo around text and buttons.
I experimented a bit and noticed that this problem disappears if I use a DisplayPort connection instead of HDMI. (Yes, I am using the cables that came with the monitor.) According to the NVidia control panel, HDMI uses a "YcbCr420" color format with a "Limited" output dynamic range while DisplayPort uses a "RGB" color format with a "Full" output dynamic range. All other settings seem to be the same and I am not given the ability to modify the aforementioned settings.
This monitor is supposed to support HDMI 2.0 and DisplayPort 1.4. My video card is a NVidia GeForce GTX 750 Ti.
My video card (like all others I've seen) only comes with a single HDMI, DisplayPort and DVI port so I cannot connect both monitors using DisplayPort. The monitors do not have integrated daisy chaining DisplayPort capability and when I researched 3rd-party hubs for doing this (dual 4K monitors at 60Hz) reviews were terrible across the board. Plus they were horribly expensive.
A final nail in the coffin: I have a USB-C to Dual HDMI adapter I want to use to connect my laptop to these monitors. I've again researched DisplayPort-specific alternatives and reviews were horrible and the products were horribly expensive.
What (if anything) can I do to get the same capability (color format / dynamic range) using the HDMI connection as I do using DisplayPort?