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I am using Ubuntu MATE 22.04. Towards night, redshift sets a color temperature of 4500K.

How to reduce the color temperature even further? Unlike the Night Light feature in GNOME/KDE, Redshift does not have any simple method to manually change the color temperature (but it might be configurable by editing redshift.conf, which is why I am asking this question).

Archisman Panigrahi
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    I set mine to 3200K in the .config/redshift.conf file on the temp-night= line. – Terrance Feb 12 '23 at 05:48
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    There is both a temp-day and temp-night setting... my choice is =3500, but man redshift provides a pretty good clue on my lunar box. – guiverc Feb 12 '23 at 05:52
  • As you can see in this answer, you can use the config file to set the temperature to something lower like 3500. – mchid Feb 12 '23 at 06:09
  • Using an edited version of the default configuration file, I have [redshift] and temp-day=3400 and temp-night=3400 and transition=1 and location-provider=manual with the default [manual] and lat=48.1 and lon=11.6 All the other lines are commented out (with a ; at the beginning of all commented out lines). – mchid Feb 12 '23 at 06:17

1 Answers1

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To expand (or to provide some contrast compared to the answer found in the duplicate post). Here's what I have in my ~/.config/redshift.conf file:

; Global settings for redshift
[redshift]
; Set the day and night screen temperatures
temp-day=3400
temp-night=3400

; Enable/Disable a smooth transition between day and night
; 0 will cause a direct change from day to night screen temperature.
; 1 will gradually increase or decrease the screen temperature.
transition=1


; Set the screen brightness. Default is 1.0.
;brightness=0.9
; It is also possible to use different settings for day and night
; since version 1.8.
;brightness-day=0.7
;brightness-night=0.4
; Set the screen gamma (for all colors, or each color channel
; individually)
;gamma=0.8
;gamma=0.8:0.7:0.8
; This can also be set individually for day and night since
; version 1.10.
;gamma-day=0.8:0.7:0.8
;gamma-night=0.6


; Set the location-provider: 'geoclue', 'geoclue2', 'manual'
; type 'redshift -l list' to see possible values.
; The location provider settings are in a different section.
location-provider=manual


; Set the adjustment-method: 'randr', 'vidmode'
; type 'redshift -m list' to see all possible values.
; 'randr' is the preferred method, 'vidmode' is an older API.
; but works in some cases when 'randr' does not.
; The adjustment method settings are in a different section.
;adjustment-method=randr


; Configuration of the location-provider:
; type 'redshift -l PROVIDER:help' to see the settings.
; ex: 'redshift -l manual:help'
; Keep in mind that longitudes west of Greenwich (e.g. the Americas)
; are negative numbers.
[manual]
lat=48.1
lon=11.6


; Configuration of the adjustment-method
; type 'redshift -m METHOD:help' to see the settings.
; ex: 'redshift -m randr:help'
; In this example, randr is configured to adjust screen 1.
; Note that the numbering starts from 0, so this is actually the
; second screen. If this option is not specified, Redshift will try
; to adjust all screens.
; [randr]
; screen=1

I have everything commented out except for:

[redshift]
temp-day=3400
temp-night=3400
transition=1
location-provider=manual
[manual]
lat=48.1
lon=11.6

I have both temp-day and temp-night set to 3400. You can adjust these accordingly.

transition=1 is probably not necessary for me because I have day and night set to the same value but this may be of interest to you.

location-provider=manual is kind of important as the automatic methods usually fail and redshift will fail to start.

  • If you have night and day set to different temperatures, you should determine your latitude (lat) and longitude (lon) and set these accordingly.
  • Of course: if day and night are set to the same temperature, you can leave these at the default coordinates (41.8 and 11.6).
mchid
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  • Somehow the automatic location works for me. But otherwise, thanks for the answer – Archisman Panigrahi Feb 12 '23 at 14:14
  • @ArchismanPanigrahi I believe the automatic works when you have the geoclue-2.0 package installed. If you also install the geoclue-2-demo you can see if the geoclue-2.0 is working properly when you get output from running /usr/libexec/geoclue-2.0/demos/where-am-i – Terrance Feb 13 '23 at 14:32
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    @ArchismanPanigrahi Even with geoclue working, I've had problems with redshift where there is an error on startup and then the fix is to reinstall geoclue-2.0 which can be kind of annoying. It seems to happen randomly but I haven't looked into why the problem occurs. Of course if you encounter this problem in the future, you can set the coordinates manually to avoid the issue. – mchid Feb 17 '23 at 03:49