Chapter 3. Colors

Launch the Global Theme module:

The window shows the current installed themes. Click on the "Get New…​" icon in the top right corner. A new window will show additional themes available for installation. In the search field at the top right, you can look for new themes to install. You can search for "high contrast" or "Acrilic Dark".

Download from High Contrast Windows 11 Themes:

The example is for NightSky, but of course you can choose whichever theme you prefer.

The theme selection steps (5 and 6) can also be performed using the graphical configuration dialogs in XFCE:

Open the Icons module:

The window displays the currently installed icon themes. To install a new theme, click the Get New…​ icon in the top right corner. A new window will appear, allowing you to browse and install additional icon themes. As a suggestion, you can search for Treepata using the search bar at the top right. Although originally designed for XFCE and later adapted for KDE Plasma, Treepata was created as a high-contrast accessibility theme.

Run the following commands to use the Treepata - High Contrast icons theme with XFCE.

Download Treepata.zip from Treepata - High contrast. Then execute:

The icon theme (step 6 above) can also be set graphically via the Appearance dialog under the Icons tab. To do so, open the dialog and select your preferred icon theme:

darkman(1) is a daemon that automatically manages transitions between dark mode and light mode. It operates primarily in the background, switching the screen’s color scheme based on the local time of the current location. To install, run:

Create the file ~/.config/darkman/config.yaml and write your latitude and longitude. Example:

The utility does not directly change the screen colors; instead, it calls external utilities to perform the color transitions. Add scripts to be executed at sundown by placing them in $XDG_DATA_DIRS/dark-mode.d/ and scripts to be executed at sunrise by placing them in XDG_DATA_DIRS/light-mode.d/. Several example scripts are available in the project repository.

To start darkman manually, run:

The utility also offers some interactive options; for more details refer to the darkman(1) manual page.

The gammastep(1) utility adjusts your screen’s color temperature automatically based on your location. To install, run:

The utility works out of the box without any configuration. Simply start it by running:

KDE allows you to adjust the screen color temperature based on geographic location and local time. Launch the Night Light module:

Enable automatic color adjustment by selecting the desired option from the Switching times drop-down menu.

The redshift(1) utility find your position and sets the color temperature accordingly. To install, execute:

The redshift utility runs without any configuration. To start it, simply execute:

The utility might hang while trying to determine the location or the correct method to set the color. In this case, specify them explicitly using -l latitude:longitude and -m method. The available methods can be listed by running: % redshift -m list.

Example of running redshift with an explicit location and method:

To make this setting permanent, add the following lines to ~/.config/redshift/redshift.conf file:

The sct(1) utility is a simple command-line tool for controlling screen color temperature. It does not update automatically and must be run repeatedly to adjust the temperature over time. To install, execute:

The utility takes temperature values between 1000 and 10000, 6500 is the default. To run sct, type: sct value:

The sctd utility calculates sunrise and sunset times based on latitude and longitude, and adjusts the screen’s color temperature accordingly. To install, run:

To run sctd, specify your location using the --latitude and --longitude options:

To reset the screen color to default, run:

The wlsunset(1) utility is a Day/Night gamma adjustments for Wayland compositors.

To install, execute:

To start the utility type wlsunset -l latitude -L longitude. Example:

The backlight(8) utility is included with the operating system. It is used to set the brightness of devices located under /dev/backlight/.

The command backlight -f device value sets the brightness of device to value, where value is an integer between 0 (dim) and 100 (bright). If no device is specified, the default device /dev/backlight/backlight0 is considered.

Example for setting the brightness of the default device to 50%:

The acpi_video(4) driver, included with the operating system, uses the ACPI Video Extensions to control display switching and backlight brightness. To load the kernel module, run:

Brightness settings can be configured using sysctl(8). The following parameters are available:

device is a possible display device. Example to set the brightness to 50% for the lcd0 device:

The x11/xbrightness utility can change the brightness via the X Window System.

The xbrightness(1) utility allows to set a value between 0 (darkness) and 65535 (full brightness). Example for setting brightness to 50%:

The x11/xrandr package is an extension of the X11 server that provides the xrandr(1) utility. It allows you to configure various display properties, including brightness. To install execute:

The command xrandr --output monitor --brightness brightness allows you to set the brightness for monitor to a value between 0 and 1.0. To list the available monitors, run:

Example for setting brightness to 50% for HDMI-1:

KDE allows you to filter colors for graphical elements. Launch the Accessibility module:

In the navigation pane, select Color Blindness Correction. Enable the Color blindness correction option, then choose the appropriate color transformation mode from the Mode drop-down menu.