Hi all,
I’m owning a wide-gammunt Monitor (Benq SW240).
All in a sudden archlinux upgraded Gnome to Version 4.x. Colormanagement worked fine in Gnome 3.x. Gnome-colormanager nor xiccd nor dispwin lead to consistent colors in Firefox, chromium, opera, Rawtherapee, darktable, xnview. They all by settings rely in system colormanagement.
Can someone confirm or maybe I’m wrong somehow in settings?
thanks in advance…
Are you using Wayland?
No, I don’t. AFAIK there is no support in Wayland for colormanagement.
This is not correct. gnome has some hacks to make colormgmt work under wayland.
Any link regarding Gnome40 and Wayland would be appreciated.
For some definition of “work” that doesn’t include things like calibration, profiling, multi-screen support, etc.
Screenshot of GNOME Settings on GNOME 40 on Fedora 34, in Wayland, specifically in the color tab, where it shows multiple devices, a button to add existing profiles, a calibration button, etc.:
(This has been around for several GNOME releases, FWIW. It’s not new.)
You can expand each device and switch profiles too (if more than one exists).
You may have a UI, but does it actually do anything ?
Lets see you pop up a calibration test window and create a set of calibration curves using a colorimeter.
If it works, you’re not actually running Wayland 
I haven’t created a profile since upgrading. Yeah, I should… at least attempt it. 
Settings are clear(X11).
“Work” is: wallpaper, menus (not important), RT → System Profile, DT → System Profile, and a least ONE image viewer (Xnview, EOG, or…).
If you have multiple devices, another colormanager (e.g. xiccd) maybe is active.
With much handworking, openbox does this. In any other environment, including KDE, one of the points does not work.
Gnome 3.x had a CONSISTENT colormanagement. Maybe it is an gtk4 issue. If one is searching in the Web, the lack of Interest leads often to “Linux sucks” or “Linux Colormanagement sucks”.
By the way, maybe Mate or Cinnamon does?
Sorry for may bad english…
With the recent 21.10 release, Gnome 40 comes to Ubuntu and it does indeed break color management. It looks as if the monitor profile is ignored, even though all the settings are correct. In apps like the GIMP or Geeqie, you can disable the system-wide monitor profile and assign your profile manually to get correct color. Web browsers seem to prefer the system-wide profile.
If you care about color management, do not upgrade to 21.10. If you know a way to fix this, please share.
Yes, please. Gnome 3.x has had the best CM, in my experience better than KDE.
Or Cinnamon, which is somewhat based on Gnome 3! 
One question, were you running 21.10 on Wayland or X11?
As an experiment I’ve booted a usb stick of Ubuntu 21.10 (which seems to be running X11 rather than Wayland)
I’ve applied a swapped red and green colour profile in the colours dialogue, and the gimp app image has picked that profile up when I enabled “try to use system monitor profile” in the colour management settings of gimp.
I’m using X11 in the “Gnome” login session. I have also tried the “Gnome Classic” and the “Ubuntu” sessions, with the same result. Meanwhile, I’ve installed Fedora 34 to a different partition, and it seems to have the same issue (uses Gnome 40, too).
Your result is intriguing. It could be that the live USB session uses a different video driver, although I’ve tried switching to Nouveau instead of the Nvidia driver and that didn’t solve anything.
What I’m seeing seems limited to programs not being able to get the monitor profile from the OS. Once you set the profile manually for each program, the color is correct. The desktop elements won’t be color corrected, but I can live with that. Firefox was a bit tricky, because in 21.10 they moved it to a snap package. I had to remove the snap and reinstall from the repository to make it use the profile assigned in about:config. Chrome & co. have a flag that enables you to force an output color space, but only from a predefined list (and sRGB doesn’t work).
What applications are you having the issues with colour management? Are they native applications, appimages, flatpacks, or snaps?
In the test I did I used the gimp Appimage. Although if i changed the colour profile on the gnome system settings, the display didn’t change in gimp immediately, i had to toggle the “try to use system monitor profile” setting in gimp preferences. Perhaps that is due to gimp (and other apps) not regularly polling the system colour profile to see if it had changed?
With my limited knowledge of Linux and Color Management, I could not get DisplayCAL to work to create a ICC profile on Fedora 34 with Gnome40 when running in Wayland. When logging in using Xserver, creating a profile was no problem. I have set the created profile in Gnome as the Color Profile for my monitor and I do remember that I had to manually select this profile in Digikam, XnView (both flatpak)
If I remember correctly Darktable (flatpak) picked up the profile by itself, not manual setting here.
As I couldn’t create a profile while running in Wayland, I log into X since then and I haven’t checked.
I haven’t tested if only creating the profile in Wayland causes problems and displaying/using the profile not. I might test that tonight…
I’m using Xfce, which has a color-profile module in settings. If setting applications to “use system profile”, some pick the correct profile, some don’t. I created the profile with displaycal. Explicit use of dispwin, etc. is not nessessary. No knowledge of wayland regarding of malfunction.
All applications I looked at are affected, notably Darktable, Gimp, Geeqie, Web browsers. They are all installed from the official repositories. Once I assign the profile manually, they all work fine.
Based on your observation, I tried toggling the system profile option. Every time I turn it back on the effect is the same as if I disabled color management altogether.
Other things I’ve tried that didn’t solve the problem: clear out all monitor profiles from the usual locations (~/.local/share/icc/, /var/lib/colord/icc/) and reinstall the current monitor profile; simplify path and filename of the ICC file; create new profile.
Not sure if it’s significant, but when I check the status of the colord service, it appears active and it logs this:
systemd[1]: Starting Manage, Install and Generate Color Profiles...
systemd[1]: Started Manage, Install and Generate Color Profiles.
colord[1928]: failed to setup Lab -> RGB transform
colord[1928]: failed to setup RGB -> XYZ transform
One more thing. If I load the system profile with the dispwin program from Argyll CMS (dispwin -I /path/to/profile.icc), then the problem is solved for the rest of that session. But I don’t know how to automate it. I’ve tried running dispwin from .profile, but I still have to run it a second time after login. Same with creating an entry for dispwin in gnome-session-properties (incidentally, this is how DisplayCAL used to run its own profile loader).