Redshift

From the Redshift project web page:

Redshift adjusts the color temperature of your screen according to your surroundings. This may help your eyes hurt less if you are working in front of the screen at night. This program is inspired by the closed-source application f.lux.

Note: Redshift does not support Wayland [1]. See Backlight#Wayland for alternatives.

Installation

Install the redshift package. Alternatively, install the redshift-minimal^AUR package, for a version with minimal dependencies.

Front ends

The redshift-gtk command comes with the redshift package and provides a system tray icon for controlling Redshift. See optional dependencies.

Alternatives are redshift-qt^AUR, redshiftconf^AUR or plasma5-applets-redshift-control-git^AUR.

Usage

Redshift will at least need your location to start (unless -O is used), meaning the latitude and longitude of your location. Redshift employs several routines for obtaining your location. If none of them works (e.g. none of the used helper programs is installed), you need to enter your location manually.

Quick start

To just get it up and running with a basic setup, issue:

$ redshift -l LATITUDE:LONGITUDE

where LATITUDE is the latitude and LONGITUDE is the longitude of your location.

Tip: You can get the coordinates of a place with GeoNames.org.

To instantly adjust the color temperature of your screen use:

$ redshift -P -O TEMPERATURE

where TEMPERATURE is the desired color temperature (between 1000 and 25000).

Autostart

There are several options to have Redshift automatically started:

By right-clicking the system tray icon and selecting Autostart when redshift-gtk or plasma5-applets-redshift-control is already launched.
By placing a Redshift desktop entry in ~/.config/autostart/ or by adding redshift to your window manager or desktop environment's autostarting method.
By using the user units provided: redshift.service and redshift-gtk.service. Activate only one of them depending on whether or not you want the system tray icon.

Note:

The Redshift service files contain Restart=always so they will restart infinitely. See systemd.service(5).
When using a systemd user service, Xorg must be started before execution of the service, which is not the case without a display manager. Otherwise you will get RANDR Query Version' returned error -1 and Initialization of randr failed. This is already accounted for in the systemd/User method above, which contains After=display-manager.service.

Toggle

Redshift will continously update the color temperature at regular intervals. One shot mode can be selected if you only want to do one adjustment. The color adjustments done by Redshift can be temporarily toggled on and off by sending it the USR1 signal:

$ pkill -USR1 redshift

Configuration

Redshift reads the configuration file ~/.config/redshift/redshift.conf [2] if it exists. However, Redshift does not create that configuration file, so you may want to create it manually. See redshift.conf.sample.

Specify location manually

Redshift calculates the sunrise and sunset times based on geographic coordinates. It can be specified manually by using the manual location-provider, e.g. for Paris:

~/.config/redshift/redshift.conf

[redshift]
...
location-provider=manual
...
[manual]
lat=48.864716
lon=2.349014

Automatic location based on GeoClue

Redshift uses the geoclue2 location-provider by default. It needs a GeoClue agent running in the background. It is supposed to work without further configuration, but if you experience problems, see #Unable to connect to GeoClue.

Automatic location based on Mozilla Location Service

Note: As of June 12th, 2024, the Mozilla Location Service has been completely deprecated. Consider configuring a custom location provider for GeoClue at /etc/geoclue/geoclue.conf. Currently, only Google Geolocation API is supported and requires an API key.

You can use cURL to get the location data and parse it into the format required by Redshift. For example, Mozilla provides json location data that can be parsed with jq as follows:

redshift -l $(curl -s "https://location.services.mozilla.com/v1/geolocate?key=geoclue^{[dead link 2024-07-30 ⓘ]}" | jq -r '"\(.location.lat):\(.location.lng)"')

or with awk if jq is not on the system:

redshift -l $(curl -s "https://location.services.mozilla.com/v1/geolocate?key=geoclue^{[dead link 2024-07-30 ⓘ]}" | awk 'OFS=":" {print $3,$5}' | tr -d ',}')

or with sed:

redshift -l $(curl -s "https://location.services.mozilla.com/v1/geolocate?key=geoclue^{[dead link 2024-07-30 ⓘ]}" | sed 's/.*"lat": \(-\?[0-9.]*\).*"lng": \(-\?[0-9.]*\).*/\1:\2/')

Automatic location based on GPSD

You can also use gpsd to automatically determine your GPS location and use it as an input for Redshift. Create the following script and pass $lat and $lon to redshift -l $lat;$lon:

#!/bin/bash
date
#gpsdata=$( gpspipe -w -n 10 |   grep -m 1 lon )
gpsdata=$( gpspipe -w | grep -m 1 TPV )
lat=$( echo "$gpsdata"  | jsawk 'return this.lat' )
lon=$( echo "$gpsdata"  | jsawk 'return this.lon' )
alt=$( echo "$gpsdata"  | jsawk 'return this.alt' )
dt=$( echo "$gpsdata" | jsawk 'return this.time' )
echo "$dt"
echo "You are here: $lat, $lon at $alt"

For more information, see this forums thread.

Use real screen brightness

Redshift has a brightness adjustment setting, but it does not work the way most people might expect. In fact it is a fake brightness adjustment obtained by manipulating the gamma ramps, which means that it does not reduce the backlight of the screen. [3]

Changing screen backlight is possible with redshift hooks and acpilight, but please see Backlight#xbacklight as there are some limitations and you may have to find another method of controlling the backlight depending on your hardware.

You need to create a file in ~/.config/redshift/hooks and make it executable. You can use and edit the following example:

~/.config/redshift/hooks/brightness.sh

#!/bin/sh
# Set brightness via xbrightness when redshift status changes

# Set brightness values for each status.
# Range from 1 to 100 is valid
brightness_day=85
brightness_transition=50
brightness_night=30
# Set fps for smoooooth transition
fps=1000
# Adjust this grep to filter only the backlights you want to adjust
backlights=($(xbacklight -list | grep ddcci*))

set_brightness() {
	for backlight in "${backlights[@]}"
	do
		xbacklight -set $1 -fps $fps -ctrl $backlight &
	done
}

if [ "$1" = period-changed ]; then
	case $3 in
		night)
			set_brightness $brightness_night 
			;;
		transition)
			set_brightness $brightness_transition
			;;
		daytime)
			set_brightness $brightness_day
			;;
	esac
fi

Make it executable and restart the redshift.service to apply changes.

Check the service status as it should not contain the following message:

redshift[..]: No outputs have backlight property

Troubleshooting

Unable to connect to GeoClue

If running $ redshift and you are getting:

Unable to obtain GeoClue client path: Timeout was reached.

Then make sure that a GeoClue agent is running. GNOME Shell provides an agent itself. For other desktop environments, a demo agent (/usr/lib/geoclue-2.0/demos/agent) is autostarted. You can check if GeoClue works properly by checking the output of the /usr/lib/geoclue-2.0/demos/where-am-i command.

If you are using a desktop environment that does not support XDG Autostart, then you have to start the demo agent manually, or you can create a systemd unit file with the following config:

~/.config/systemd/user/geoclue-agent.service

[Unit]
Description=redshift needs to get a (geo)clue

[Service]
ExecStart=/usr/lib/geoclue-2.0/demos/agent

[Install]
WantedBy=default.target

Then start/enable the geoclue-agent.service user unit.

Screen 1 could not be found

Locate configuration-file "redshift.conf" in your distribution and change "screen 1" to "screen 0".

Left/right clicking the tray icon does not work

Install libappindicator-gtk3. See redshift issue 363 and FS#49971.

Redshift makes the screen quickly flicker between the set color value of the screen and the default color value

Make sure there are not multiple instances of redshift running.

Redshift works fine when invoked as a command but fails when run as a systemd service

The systemd unit has a line in the redshift.service file that makes the service wait until the display-manager.service unit is started by a display manager before the unit will invoke redshift. If you do not use a display manager, edit the redshift.service user service and delete the After=display-manager.service line. Run a daemon-reload and the service should initialize properly.

Redshift-gtk service causes core-dumping

Refer to the previous problem and to [4].

Redshift does not appear in system tray

If running the $ redshift-gtk command does not start in the system tray, but instead you get the following output

$ redshift-gtk

Traceback (most recent call last):
  File "/usr/bin/redshift-gtk", line 26, in <module>
    from redshift_gtk.statusicon import run
  File "/usr/lib/python3.8/site-packages/redshift_gtk/statusicon.py", line 31, in <module>
    gi.require_version('Gtk', '3.0')
AttributeError: module 'gi' has no attribute 'require_version'

you will need to install python-gobject.

Redshift temporarily resets using some wine applications that reset gamma values

If you notice that using some wine applications, redshift seems to reset temporarily upon launch, or adjusting settings, or etc, then there is a useful registry key that seems to alleviate this. See [5]^{[dead link 2024-10-19 ⓘ]} and [6]. Set or create the string value

HKEY_CURRENT_USER\Software\Wine\X11 Driver

UseXVidMode="N"

using the registry editor, or import/set it otherwise.

Redshift turns the screen green when resolution is over 1080p while using Nvidia drivers

This is a bug with the nvidia drivers. A fix for this is to make the following edit:

/etc/X11/xorg.conf.d/20-nvidia.conf

Section "Device"
    ...
    Option         "UseNvKmsCompositionPipeline" "false"
    ...
EndSection

For more information, see redshift issue 587 and redshift issue 720.

Redshift does not support hotkey for toggling

A workaround is to create a custom hotkey in your desktop environment calling the command pkill -USR1 '^redshift$'.

For more information, see [7].