The Inconvenient Dimming
When running Ubuntu Linux on a laptop, the GNOME desktop environment employs several tactics to stretch your battery life. One of the most noticeable features is screen dimming. If you stop typing or moving the mouse for a relatively short period (often just a few minutes), Ubuntu will automatically reduce the brightness of your display to save power before eventually suspending the system. While logical for battery conservation, this feature is incredibly annoying if you are reading a long article, referencing a block of code on a secondary monitor, or simply watching a process complete in the terminal. The screen constantly fades to black, forcing you to frantically wiggle the mouse to restore the brightness.
How to Disable Screen Dimming in Settings
You can easily turn off the automatic dimming behavior without completely disabling the system’s ability to eventually go to sleep.
1. Open the Settings application. You can do this by clicking the system menu in the top-right corner of the screen and selecting the gear icon.
2. In the left-hand navigation sidebar, click on Power.
3. Look at the section labelled “Power Saving Options.”
4. Locate the toggle switch labelled Dim Screen (or “Dim Screen When Inactive” depending on your exact Ubuntu version).
5. Click the toggle switch to turn it Off.
With this setting disabled, your display will maintain its full, set brightness level indefinitely while you are working. If your system is still configured to sleep after 15 minutes of inactivity, the screen will remain at 100% brightness until the 15-minute mark, at which point it will immediately turn off and suspend.
How to Manage Brightness via the Terminal (gsettings)
If you are configuring multiple machines or prefer using the command line, you can adjust this specific power setting using `gsettings`.
1. Open your terminal.
2. Run the following command to check your current setting (it will return `true` if dimming is enabled, or `false` if it is disabled):
gsettings get org.gnome.settings-daemon.plugins.power idle-dim
3. To completely disable the automatic screen darkening feature, run the following command to set the key to false:
gsettings set org.gnome.settings-daemon.plugins.power idle-dim false
The changes take effect immediately without requiring a reboot.