I have a new MBP 2019 16" with the AMD Radeon Pro 5500M 8 GB vid card.

When I plugged my LG UltraFine 5K display in via USB-C I noticed strange light blue aliasing around font and images.

Example (bad):

enter image description here

Here is the same text (in same window) but on the MBP built-in retina display: enter image description here

It doesn't show up great here, but its very obvious to the naked eye.

It happens on everything (not just font): enter image description here

What is strange is I do NOT see this issue if I change the display resolution scale to 2560x1440 or below in Display Settings:

enter image description here

I know it is NOT a problem with the external monitor, because when I plug it into my late 2018 15" MBP I do not see the problem.

I have a second 4K LG monitor plugged in at the same time, and it is not exhibiting this issue (no matter what resolution scale is selected).

I've tried:

  • Disabling font smoothing
  • Restarting
  • Changing monitor color profiles
  • Using f.lux
  • Only plugging in the UltraFine 5k

Any ideas what this is called or how I might fix? This is SUPER annoying.


The current workaround is to disable True Tone in Displays prefrence.

Not ideal obviously. Hoping someone from Apple picks up on my discussion here

  • I'm experiencing this too in the LG UltraFine 5K display, and there's no way to disable Truetone in clamshell mode. But even when I do open up my laptop to disable True Tone, that doesn't have any bearing on the aliasing going on in the external display. Still persists. – Martyn Chamberlin Mar 26 '20 at 16:33

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