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.
redshift -h for help on command line options. You can run the program
redshift-gtk instead of
redshift for a graphical status icon.
Redshift applies a redness effect to the graphical display. The intensity of the redness can be customized and scheduled to only be applied at night or to be applied with more intensity at night.
Redshift uses the gamma correction ramps to apply this effect which has traditionally been the only way of applying a color effect to the display. Note that this is really a hack to work around the absense of a standardized way of applying color effects, and it is resulting in several issues some of which are explained in the FAQ section below. As long as Redshift is using gamma ramps, many of these issues are impossible to solve properly in Redshift.
Since Redshift was first created, many desktop environments have adopted similar functionality as an integrated component:
Using the features integrated into the desktop environments avoids many of the issues with gamma ramps which is why these implementations should generally be favored over Redshift. On the other hand, Redshift may offer some additional flexibility that is not available in the integrated features.
Use the packages provided by your distribution, e.g. for Ubuntu:
apt-get install redshift or
apt-get install redshift-gtk. For developers,
please see Building from source and Latest builds from master branch below.
A configuration file is not required but is useful for saving custom configurations and manually defining the location in case of issues with the automatic location provider. An example configuration can be found in redshift.conf.sample.
The configuration file should be saved in the following location depending on the platform:
~/.config/redshift/redshift.conf(if the environment variable
XDG_CONFIG_HOMEis undefined) or
There are multiple web sites that provide coordinates for map locations, for example clicking anywhere on Google Maps will bring up a box with the coordinates. Remember that longitudes in the western hemisphere (e.g. the Americas) must be provided to Redshift as negative numbers.
It is possible that the location services have been disabled completely. The check for this case varies by desktop environment. For example, in GNOME the location services can be toggled in Settings > Privacy > Location Services.
If this is not the case, it is possible that Redshift has been improperly installed or not been given the required permissions to obtain location updates from a system administrator. See https://github.com/jonls/redshift/issues/318 for further discussion on this issue.
Certain video drivers do not support adjustable gamma ramps. In some cases Redshift will fail with an error message, but other drivers silently ignore adjustments to the gamma ramp.
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. Preferably only use it if your normal backlight adjustment is too coarse-grained.
The Wayland protocol does not support Redshift. There is currently no way for Redshift to adjust the color temperature in Wayland.
Instead, you can use:
Mir does not support Redshift.
You need to export your environment variables when your window manager or compositor start up. Typically, you want to run this as part of its startup:
systemctl --user import-environment; systemctl --user start graphical-session.target
See your compositor's (or window manager's) documentation for further details of setting up the systemd user session.
Related issues: #753.
This usually happens to users in America when the longitude has been set in the configuration file to a positive number. Longitudes in the western hemisphere should be provided as negative numbers (e.g. New York City is at approximately latitude/longitude 41, -74).
Redshift uses the gamma ramps of the graphics driver to apply the redness effect but Redshift cannot block other applications from also changing the gamma ramps. Some applications (particularly games and video players) will reset the gamma ramps. After a few seconds Redshift will kick in again. There is no way for Redshift to prevent this from happening.
You may have multiple instances of Redshift running simultaneously. Make sure that only one instance is running for the display where you are seeing the flicker.
Mouse cursors are usually handled separately by the graphics hardware and is not affected by gamma ramps. Some graphics drivers can be configured to use software cursors instead.
Please go to the issue tracker and check if your issue has already been reported. If not, please open a new issue describing you problem.
See the file CONTRIBUTING for more details.