How to reduce the brightness lower than supported by my display?

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KDE Discuss thread

Introduction on Android

On Android there are 2 ways to reduce the display brightness to lower than normally possible. One is the built in “extra dark” which applies a set transparent black overlay on top of the display. The other one is “Red Moon” which is more customizable and allows blue-light filtering and a customizable dark overlay.

As phones use OLED screens, this works perfectly and actually reduces the brightness of all non-black elements well.

My Laptop has an IPS display so it should have true black colors, but I am not sure about the other brightness gradients. I assume this would work equally well though.

KDE builtin tool

KDE Plasma has a builtin tool for blue-light reduction and it works great. But it lacks the dark overlay feature to reduce the overall brightness.

Plasmoid, gammastep, redshift

There is a Plasmoid called “Redshift control” and it allows using redshift or gammastep.

I tried both tools, and I am not sure if they work on wayland at all.

Redshift is abandoned and has no wayland support afaik.

gammastep
Error: Could not control gamma, exiting.
Error: Failed to start adjustment method: wayland

Gammastep supports wlr-gamma-control-unstable-v1 protocol for wlroots-based
wayland compositors.

So I assume no kwin support yet. Waycheck flatpak shows me “N/A”, I will try the Fedora package for more access.

The dev recommends to disable these gammastep things

rm ~/.config/autostart/gammastep-indicator.desktop
systemctl --user disable --now gammastep-indicator
systemctl --user mask gammastep-indicator
systemctl --user disable --now gammastep
systemctl --user mask gammastep

Other options?

I tried to find a KWin script but not sure if that is the right place to search.

Anyone know if such a thing exists?

For GNOME, the “color tint” extension seems to do the trick

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I know there is a replacement for redshift… just can’t find it now…
There is qredshift, but looks to only be for x GitHub - raphaelquintao/QRedshift: Linux terminal app to change screen color temperature.

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This is old and I know that you specifically state lower than supported by my display. But just in case, there’s a tool called brightnessctl that allows more granular control for laptop displays. Running brightnessctl set [value], with value being lower than reported may give you the result you want.

GitHub - Hummer12007/brightnessctl: A program to read and control device brightness

Explanation: Reduce Fedora/Debian/Ubuntu screen brightness using /sys/class - Bizanosa

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Indeed, brightnessctl set 0 is a bit lower than 0% in KDE Plasma

Also this fixes my “set brightness via kde connect” issue

sh -c 'brightnessctl set $(($(brightnessctl get) - 3)) || brightnessctl set 0'

Would reduce the brightness

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@boredquirrel, not for me:

  1. #!/usr/bin/env sh
brightnessctl set 0

  2. Updated device 'amdgpu_bl1':
Device 'amdgpu_bl1' of class 'backlight':
        Current brightness: 0 (0%)
        Max brightness: 62194

…with:

    1. #!/usr/bin/env sh
hwinfo --monitor | grep -E 'Model|Serial ID'

    2. Model: "BOE CQ LCD Monitor"
Serial ID: "0"

  • kcmshell6 kcm_about-distro’s “Copy Details”:

    Operating System: Fedora Linux 42
KDE Plasma Version: 6.4.4
KDE Frameworks Version: 6.17.0
Qt Version: 6.9.1
Kernel Version: 6.16.4-200.fc42.x86_64 (64-bit)
Graphics Platform: Wayland
Graphics Processor: AMD Radeon 780M Graphics
Manufacturer: Framework
Product Name: Laptop 16 (AMD Ryzen 7040 Series)
System Version: A7

Consequently, that might be a deficiency in (PowerDevil’s) support for your display. Unlike this laptop display, yours might be (faultily) DDC-controlled…?