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Night Shift on LG 38WN95C only works in PBP.

S

SirThanksalot

macrumors member
Original poster
Jun 25, 2020
34
1
Hi guys,

I have a strange problem with my external monitor. I have an ultra-wide LG 38WN95C hooked up to my MacBook Pro 16" running Big Sur (although I had the same problem on Catalina). I noticed a while ago that night shift is not turning on. At first I thought, that the display does not support it (despite the specifications saying it does), but it is even stranger than I thought.
When connecting the display over thunderbolt (basically everything is hooked up to the monitor and the monitor is then connected to the MBP) I get no night shift. However, when I turn on the PBP (picture-by-picture, so one half TB one half HDMI) everything works! Turn PBP off and it's back to blue light again. I am really not sure, what the issue here is. I don't assume night shift is limited by resolution. Any ideas?

Best regards
 
I've been looking for the same answer. I have the LG 38WK95C, connected to both a MacMini 2014 and a MacMini 2020 M1.

I've been tinkering, and discovered a few things, but no answer yet.

I had installed the HueSync app, which I thought prevented Night Shift on any connection. When I connected my MacMini 2014 and uninstalled Hue Sync — completely; I had to go in to the library and manually remove a few left over files — still no night-shift if on full-screen, regardless of the connection. But, after a bit more testing, I realise I can now replicate that on the MacMini 2020 with Hue Sync installed.

That is, no matter which machine I'm on, I get the same as you:
  • Full-screen — no Night Shift
  • PBP Display Port or USB-C — no Night Shift
  • PBP HDMI — Night Shift
(Discovered also, it's not possible to have PBP using USB-C and DisplayPort. It's USB-C/DisplayPort and HDMI only.)

So, maybe there is a maximum screen resolution supported by Night Shift? I just spent some time tinkering with different resolutions, using SwitchResX to work my way through a heap, but that seemed to make no difference, even going down to a ridiculous 640 x 480!

So, it must not be resolution. Perhaps then it's a matter of aspect ratio? Why would that make a difference?

And yet, it seems that combination of HDMI and screen aspect determines whether or not Night Shift works on these monitors. 🤷‍♂️
 
Wow, ok, at least I'm not the only one. Going by this thread here it seems the problem is not the system as in #9 you can see the poster getting full resolution, Night Shift and even high refresh modes on Big Sur. Is that a LG issue, after all?

Yes, USB-C + DP does not work... It's only DP + HDMI1/2 or USB-C (or TB in my case) + HDMI1/2. Kind of a bummer, but that would be fine if everything else was working...

On my Windows machine the display seems to be working better (full resolution + 144Hz and all), it's only the Mac that does not work.

On a side note, since I can't use the media buttons for volume and brightness, I tried MonitorControl, but it does not recognise the monitor, so I guess there are more issues other than night shift...
 
SirThanksalot said:
That is just sad. But with it being a software issue I assume there is a workaround. Does your WK work with MonitorControl?
Click to expand...
There's an app provided by LG called "OnScreen Control". Is that what you're referring to? It worked on my old Mac, running Catalina, but it doesn't recognise that I have a monitor connected on the new one running Big Sur.
 
Hi all.
Yesterday I purchased a Lenovo ThinkVision P44w-10 (well it's second-hand, but unused, for a fraction of a price ... but no returns) and I also have a problem of Night Shift option being gone.

Before that I used two identical 24" 1080p Philips monitors - one via native DP (through ThinkPad 40AC TB3 dock) and the other one via DisplayLink adapter.
Night Shift (and also True Tone) worked on that native DP output without a problem.
But I wanted Night Shift on both screens and maintain big screen real estate so I bought this P44w-10 (32:10 3840x1200).

So far I am a bit disappointed. Night Shift kinda works, but it's borked.
There is NO option for Night Shift in Display Preferences.

The only way how to turn it on is to activate PBP via the button on the monitor - then it starts to mirror two 1920x1200 screens one by another ... and guess what ... with Night Shift enabled. But there is still no option in Display pref. and it cannot be adjusted/turned off. Then I press the button again and it becomes one ultrawide screen with that borked Night Shift.

So now basically after every boot (fortunately there is almost no need to power off / restart an M1 Mac) I have to press the button for PBP, wait a few seconds and then press it again to "enable" Night Shift.

Details about connection:
I use it connected with TB3 cable connected to the monitor's 10Mbps USB-C alt-mode input (although the monitor is not TB3 ... but haven't unpacked the Type-C cable that came with the monitor .. shouldn't make any difference tho... I like things unpacked... don't judge me).

I've also tried monitor's DP input - which is DP1.4 ... but I only have what I presume is DP1.2 Type-C->DP dongle and a cable ... also no Night Shift option there

Then I tried to run it off the DP1.2 on the TB3 dock... same result. And also via the TB3 passthrough port on the dock (again the dongle) also with the same result.

Strange thing is that some guy on reddit also had a problem with P44w-10 - the resolution ... but in the picture he posted I can see that he had an option for Night Shift ... but he was running Catalina at the time.
y7lnzg3nlv751.png


I even installed the latest FW on the monitor - thankfully I recently bought a Windows laptop to my collection - a ThinkPad T480s so I could perform the update.

I don't know what to do next ... I mean I can live with that... but it's a bit annoying. Any help is appreciated.
 
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