Your screen light is typically set to a blue shade for better viewing. However, at night time this blue light puts some extra strain on our eyes; so a better approach is to switch to a warmer light by activation of the Night Light feature. Another disadvantage of using the blue light at night is that it tells your brain that is is day time. This disrupts your circadian rhythm which means low immune system, melatonin loss and thus sleep disturbance.

In this article, we will explain how you can activate the night light feature using both the Debian GUI and its command line(Terminal).

We have run the commands and procedures mentioned in this article on a Debian 10 Buster system.

Activate Night Light Through the Settings Utility (UI-based method)

If you prefer using the GUI for performing simple administrative tasks, you can make use of the graphical Settings utility.

You can access the Settings either through the system Application Launcher search(access it by hitting the Super/Windows key) or by accessing it as follows:

Click on the downward arrow located at the top-right corner of your Debian desktop and then click the settings icon from the following view:

Open GNOME Settings

The Settings utility opens in the view you were on when you last opened Settings. You need to click on the Devices tab, and then the Displays tab in order to configure night light on your Debian.

Alternatively, you can directly launch this view by entering relevant keywords such as “night light” or “displays” in the Debian Application launcher search, as follows:

Search for night light

This is how the Displays view looks like:

Display settings

Click on the Night Light feature; the following Night Light dialog will appear:

Turn on night-light feature

Through this dialog, you can enable the Night Light feature by turning the slider button ON.

You can also schedule your system to automatically enable this feature from Sunset to Sunrise. This is the time automatically picked up by your system from the Internet according to your time zone. You can also set a From and To time manually through the Manual option in Schedule. As soon as you configure the settings, they will immediately take action.

Activate Night Light Through the Terminal (CLI-based method)

For a Terminal-savvy person who likes using the command line for most operations, we have two solutions to activate Night Light here. Open the Terminal application by pressing the Super(Windows) key and searching for it through the Application Launcher as follows:

Open Terminal

You can use one of the following two commands from your Terminal and the night light will be activated right then:

Option 1:

$ gsettings set org.gnome.settings-daemon.plugins.color night-light-enabled true

Use gnome settings

Or,

Option 2:

$ dconf write /org/gnome/settings-daemon/plugins/color/night-light-enabled true

Use dconf

When you use one of these commands to enable night light, it will be automatically scheduled to be activated according to the sunrise and sunset timings fetched from the Internet.

In order to turn off night light, you can use one of the following two commands:

Option 1:

$ gsettings set org.gnome.settings-daemon.plugins.color night-light-enabled false

Or,

Option 2:

$ dconf write /org/gnome/settings-daemon/plugins/color/night-light-enabled false

Now you have two options through which you can be easy on your eyes at night time; enabling night light through the Debian Settings utility, or through the command line.

How to Activate Night Light on a Debian GNOME Desktop