OSX 10.15.4 colour problem on external monitors

Can confirm this seems to also be an issue on the LG32UK550 - I've run the applescript mentioned in another comment and it seems to work sometimes. Seems to be random whether turning HDR off in the display preferences works or not. Recently upgraded to 10.15.6 and this issue started happening.

With HDR mode turned on colours are washed out and hazy looking (tried a few different HDR "modes" using the LG on screen display, but none of them are really workable)

Turning HDR mode off gives terrible colours (contrast is waaay to high, colours look neon as others have mentioned and text isn't nearly as smooth)

Toggling HDR on and off seems to eventually get me to a point where the monitor doesn't get locked into HDR mode and the screen is usable again, but this is hardly ideal as it happens anytime the monitor wakes up...

My set up is a 2018 Macbook Pro 15" running Catalina 10.15.6 connecting via TB3 to a CalDigit T3 Plus dock, then to LG monitor via DisplayPort (set to DP1.2 on the LG monitor)

I have a monitor like this too with Mac Mini. Turning the display off and on helps. But I'm waiting for Apple to fix it too ... :-(

I have the same problem. I have LG 27UK850 and 2017 Macbook Pro 15. But even when I disable the new HDR option in Display preferences, the colours are still the same - the display still switches to HDR after waking up. Sometimes it's OK, sometimes not. I have to reconnect the display, but even then, it's like 50/50. I think it's a bug in MacOS 10.15.4 that still tells the display to wake up to HDR mode with all those crazy colours. I hope they'll fix it soon.

I need to correct myself – with HDR enabled in Display Preferences, the display switches to HDR and the colours are washed out and weird (like red is really a neon pink etc.), but with HDR disabled, the display switches to something (there is a popup in the right corner saying it's HDR) and the colours look totally different – like a 256 colours scheme. Both option are totally unusable. So in any case, there is a problem that started after I updated to 10.15.4 and I haven't found a reliable fix yet. Btw. I tried different connections (USB-C to Displayport, USB-C to USB-C, with a USB-C cable as well as Thunderbolt 3 cable) and the issue is there with each of these connections.

FWIW, this problem also occurs with the iPad Pro 4th Gen (2020). I have the 12.9” model, connected to a LG 27UL850 with a USB-C (10 GBPs) cable. If the iPad’s Display settings for the external display are set to “HDR” I get the same horrible washed out colours and blown out reds turning to bright crimsons etc. I tried watching sample HDR videos in both HDR10 and Dolby Vision and it made no difference. I can easily see what the HDR videos are *supposed* to look like by watching HDR video on the iPad’s built-in HDR display.

I appreciate the OP’s issue is about Macs, not iPads, and this is not an attempt to thread-hijack. I just thought it’s interesting that this also happens with the iPad Pro’s USB-C external display functionality, and haven’t found any other threads about this issue. Although iPadOS is a totally different OS and the underlying hardware is obviously different to Macs, it’s interesting that these same HDR symptoms occur, with the same blown out reds and other colours washed out.

Hope Apple fixes this up soon.

I have exactly the same problem - my LG monitor shows colours that are way too red. I have tried different cables and still get the issue when using HDR. Turning off HDR seems to defeat the purpose of investing large sums in expensive monitor equipment, and I understand apple do recommend LG monitors (especially that they do sell two models in their online store). Will apple be able to patch an update to fix this issue? I am using the new 2020 iPad Air which has usb-c. Also tried with iPad Pro 2018 model; and 2020 Mac book pro with the same issues regarding HDR.

Also when using YouTube on iPad, the resolution gets limited to 1080p and you can’t select 4K without unplugging the monitor (upper limit blocks it). When I unplug the iPad I can select 4K HDR (2160 HDR).

i was really wishing for a seamless experience, I share all frustrations of other members in this thread.

I tried calibrating, and that helped a little.

I am able to turn the HDR off, but that doesn't totally fix it.

I am working on the firmware upgrade now.

Check if night shift is enabled and turn it off.

You may also try closing the laptop lid and see if that helps.

I also have trouble with colors on my LG 27UK850 (USB-C Thunderbolt) after upgrading to 10.15.4 on a Macbook Pro 15,3. The whites look gray and the reds are too hot. It's hard to look at. (Connecting an old Macbook Pro via displayport shows correct colors.)

Thoughts...

Color Profiiles: Has anyone had luck changing the color profile? I tried them all, and calibrating but none worked.

Firmware: I also tried to upgrade the firmware, as there is a recent update available from LG. However this command failed in the terminal. Has anyone successfully upgraded firmware as a fix.

HDR: I could not find any HDR controls as referenced in this thread available in MacOS system preferences. The LG's internal menu options are limited when using USB-C, and nothing worked.

Hope somebody finds a fix!

Firmware link for LG 27UK850:

https://www.lg.com/us/support/software-firmware-drivers?customerModelCode=27UK850-W&csSalesCode=27UK850-W.AUS&category=CT10000030&subcategory=CT10000033

Same problem as others have listed. 2019 MBP 15" and LG HDR monitor 27UL600. In HDR mode, colors are completely blown out (Red appear bright pink, for example). When I switch HDR off, the color is better, but not as crisp as pre 10.15.4 upgrade. Annoyingly if my MBP goes to sleep, when I wake it back up, the monitor color is off again (and seems that much harder to get it back to normal).

I have tuned off the HDR feature, but now my LG screens are super screwed up color-wise and I can't seem to fix it. Every time it goes to sleep or restarts there is a new adventure in awful color on the LG Screens. Again I have 2018 MacBook Pro and the Monitors are LG 34BK95U and LG 27UK850...Please please Apple Tech people take note of these issues and please fix ASAP.

Yep, I was disappointed to see that. This is probably because this issue affects such a small part of their user base that it’s not worth their time. I think it’s only some LG HDR monitors that exhibit this.

I wish they would make it easy to downgrade, Catalina is a disaster for me in so many ways and Mojave was just better.

That's my problem, too. I have a 38-inch ultra-wide LG display connected via Thunderbolt 3 (USB-C) cable. No problem before...

Mac Mini (2018) and LG 38WK95C display

:-(

Krisztian

from Hungary

Not checked. Never. Display switch off and on usually solves the problem. But it's ... annoying. 😠

Mac Mini 2018, LG 38" UltraWide 38WK95C-W, Thunderbolt 3 connection

I have the same problem with my external LG 27UK850 after my last update last night on my iMac Pro, any solution to fix this problem ? The colors looks strange and the green is to green etc.

Yours

Hans-Olav Hansen