Linux Mint 21.3 “Virginia” is preinstalled with Redshift application which can be used to activate night light feature. Redshift will detect your location (latitude, longitude) to activate night light. Come a question, “how to force Redshift to activate night light all the day?”. You can modify config file to achieve this.
Edit or create /home/[username]/.config/redshift.conf file and put the following configuration:
[redshift]
; Set the day and night screen temperatures
temp-day=3350
temp-night=3350
fade=1
Save the file and restart Redshift.
If you get flicker screen, check the running process (ps ax) whether it has double Redshift processes. Kill all Redshift processes and start the new one.
$ ps ax | grep redshift
$ killall -9 redshift
