Something resets my monitor colour calibration when I log in

submitted by ffhein edited

I have calibrated my monitors to create icc profiles, they show up in KDE color management and everything used to work exactly as it should. Now every time I start my computer it goes like this:

1) I log in to my account 2) It shows my desktop, with the right colour correction. 3) After a few seconds the colours revert to look un-calibrated on both monitors. 4) I restart the colord service and it loads the colour correction again.

As an alternative to step 4, if I go to KDE colour settings, select the default profile and then back to my profile then it also starts looking good again.

This problem must've started a week or two ago, but unfortunately I haven't been able to pinpoint exactly when. I haven't touched anything related to colour management in months, and don't think I've done any changes to my system other than upgrading packages.

Can't see anything colour related in the syslog except colord loading the correct profiles. I removed all the old profiles that I wasn't using anyway. I removed dispcal's profile loader from autostart to make sure it wasn't interfering with something. The profiles are both installed system wide and in my user folder.

Using Fedora 39 KDE.

Anyone have any idea what could be wrong, or even how to debug this?

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Is that on Xorg, or on Wayland? On Xorg, a bunch of different processes can try to take control over the gamma_lut of a screen (like night light in KWin vs the gamma settings page vs some games like CS2 vs colord), so if you're on Xorg I'd be surprised if you didn't have issues with it sooner...

ffhein [OP]

Xorg, but it has worked without issues on Fedora for over a year, and it also worked on Xubuntu before that :/

I know nvidia-settings messes up the colors if I open its GUI, but I haven't found any other program which does so. I do use nvidia-settings from a script when power limiting + overclocking my GPU, but I have verified that it doesn't mess with the colours, and I've also had it for almost a year so it's not new.

Skull giver , edited

I have this on Gnome all the time. Sometimes it's games, sometimes it's something like remote desktop. It's especially jarring at night, because Gnome seems to use the colour profile as a way to implement night light and I suddenly get blasted in the face by a flash of white.

I think this is something only X applications can do, so you should check the autostart applications. Probably best to disable them all, see if it's fixed, and if so, start enabling them one by one until the problem goes away. (I'm referring to the XDG autostarting applications, not the ones in the various shell profile files in $HOME).

I've never had this happen on Wayland, but Wayland has other issues for me. One day Nvidia's driver will be good enough one day…


I am so glad to have come across this post because I thought I was going crazy. My colour was resetting and darkening, figured I was somehow hitting the button by mistake for it on my monitor to change between a preset or something. Had no idea the monitor could be controlled from the pc like that?

Glad I am not the only one having this problem

ffhein [OP]

Colour management/correction is done by the computer without involving the monitor afaik.

But I have a suspicion what might be causing your issue.. Computers can indeed control monitor settings such as brightness and power on/off through something which I believe is called DDC/CI (in case you wanna search for more information). When I bought a new Dell monitor I got an issue where it would randomly change brightness every now and then. I have my Linux PC hooked up to 2 monitors, and my work Windows laptop also connected to one of them. So while I was working, my own PC would think that I was idle and dimmed the screens. However, unlike my old monitors, the Dell would accept DDC/CI commands on all connections, not only the selected one. I just turned off monitor dimming in KDE control panel power settings as a workaround, and let it turn the monitor signal off immediately on inactivity.

While researching the issue, I also came across multiple posts by people having problems with Dell monitors randomly changing brightness, with only one computer connected, so it could also be that.. Dell has a reset procedure which they claim should fix it, but it's different for pretty much every model, so you'll have to find the one for yours, in case you have a Dell monitor. Some people wrote that it didn't work and they had to RMA the monitors.