Hmm, cannot reproduce.

On neon unstable edition night color stops working when I open system settings > display and monitor. If I select and apply another operation mode, night color works but it stops again when I close system settings. This behavior only occurs on X11.

Operating System: KDE neon Unstable Edition
KDE Plasma Version: 5.17.80
KDE Frameworks Version: 5.64.0
Qt Version: 5.13.1

> Temparature should be kept when we go to gamma, or at least reapplied when we
> leave this settings.
Due to the nature of X11, this is CANTFIX. Although, maybe it's possible to fix gamma kcm so it doens't try to update gamma ramps for no apparent reason.

https://github.com/maandree/libcoopgamma is a proposed solution.

Thanks, I didn't know about that project. It looks promising but it doesn't fix the root cause of the problem, which is X11 itself or rather the fact that the XRANDR extension allows any client to change gamma ramps.

*** Bug 413300 has been marked as a duplicate of this bug. ***

(In reply to Vlad Zahorodnii from comment #3)
> > Temparature should be kept when we go to gamma, or at least reapplied when we
> > leave this settings.
> Due to the nature of X11, this is CANTFIX. Although, maybe it's possible to
> fix gamma kcm so it doens't try to update gamma ramps for no apparent reason.

Check how it's implemented in Gnome, IIRC they don't have this issue.

I am having the same issue (Night Color disengaging) when I open the NVIDIA X Server Settings in KDE Neon 5.17.4.

*** Bug 417426 has been marked as a duplicate of this bug. ***

*** Bug 419053 has been marked as a duplicate of this bug. ***

I have the same issue. Night Color and Gamma Correction can’t be used at the same time. As soon as Night Color becomes active, gamma is reset to 1.0, and as soon as something changes gamma, temperature is reset to 6500K.

Do I understand it right, that X11 doesn’t allow to set both gamma and temperature?

X11 changes both gamma and temperature via gamma ramps. If one tool changes the ramps, the changes from the other tools are lost, unless they would be using some cooperation (see comment 4).

*** Bug 426121 has been marked as a duplicate of this bug. ***

Just wanted to confirm I am seeing this, too, on the latest stack.

Plasma: 5.21.0
Frameworks: 5.79.0
QT: 5.15.2
NVIDIA: 460.39
on xorg (latest for whatever that matters)

I can reproduce:

System Settings -> Display Configurations -> Compositor: Hit or miss, sometimes it breaks night color, sometimes not. most times it doesn't.

System Settings -> Display Configurations -> Gama: Always breaks

NVIDIA Control Panel: Always breaks

Crossover Office -> Office 2016: Always breaks night color

Those are so far the places I can see night color breaking. The crossover office one is kind of strange, but, figured I would include it anyways. I can test tomorrow on my Intel laptop (well, prime using the intel gpu), and on an AMD rx 5500 box to see if they are different.

Can confirm this as well. Just opening Compositor sometimes disabled it and just opening gamma always disabled it.
Even if these conflict (and it's therefore cantfix), it should happen when you change something and not just by opening the settings page.

I can confirm the behavior.
Perhaps it's same root cause? https://bugs.kde.org/show_bug.cgi?id=428357

*** Bug 441427 has been marked as a duplicate of this bug. ***

*** Bug 448388 has been marked as a duplicate of this bug. ***

Confirmed, too:
Operating System: openSUSE Leap 15.4
KDE Plasma Version: 5.24.3
KDE Frameworks Version: 5.90.0
Qt Version: 5.15.2
Kernel Version: 5.14.21-150400.11-default (64-bit)
Graphics Platform: X11
Processors: 4 × Intel® Core™ i5-5300U CPU @ 2.30GHz
Memory: 11.6 GiB of RAM
Graphics Processor: Mesa Intel® HD Graphics 5500

This bug is especially annoying, as the default view on openSUSE is Icon View.  In this view, night color gets already disabled when clicking on Display and Monitor icon.  After switching to Sidebar View, behavior is the same as described here.

*** Bug 456460 has been marked as a duplicate of this bug. ***

In my case, Night Color stops working when leaving/entering System Settings. So if at least System Settings could be fixed to not interfere with Night Color, it would solve the issue for me...

This issue has migrated to KDE Plasma 6 Wayland.

 STEPS TO REPRODUCE:
1. In "System Settings" go to "Input & Output" > "Display & Monitor" > "Display Configuration"
2. In the field "Color Profile" specify the path to the ICC color profile file (.e.g., /usr/share/color/icc/colord/Rec709.icc)
3. In "System Settings" go to "Appearance & Style" > "Colors & Themes" > "Night Light". Set "Switching times" to "Always on night light"

OBSERVED RESULT:
"Night Light" does not work until the user disables "Color Profile" and re-applies "Night Light"

A possibly relevant merge request was started @ https://invent.kde.org/plasma/kwin/-/merge_requests/4827

Git commit b24505a447a992634380acc223aa617e670106ef by Xaver Hugl.
Committed on 22/12/2023 at 14:00.
Pushed by zamundaaa into branch 'master'.

backends/drm: fix night color with ICC profiles

Until night color is dealt with properly by adjusting the output whitepoint,
the channel factors have to be multiplied in with the color transformation
matrix manually

M  +1    -1    src/backends/drm/drm_egl_layer_surface.cpp
M  +6    -2    src/backends/drm/icc_shader.cpp
M  +1    -1    src/backends/drm/icc_shader.h

https://invent.kde.org/plasma/kwin/-/commit/b24505a447a992634380acc223aa617e670106ef