Redshift toggles on and off (flickering)

Question

I installed redshift on ubuntu 16.04 to reduce blue light. However, when I turn it on, it toggles on and off every 1-2 seconds continuously. I ran it in verbose mode (redshift -v) and this is the output:

Temperatures: 3500K at day, 3500K at night
Solar elevations: day above 3.0, night below -6.0
Brightness: 1.00:1.00
Gamma (Daytime): 1.000, 1.000, 1.000
Gamma (Night): 1.000, 1.000, 1.000
Status: Enabled
Period: Night
Color temperature: 3500K
Brightness: 1.00

The location is set as well.

Answer 1

I had the same problem. For me, I had a redshift-gtk process running in the background and didn't know, so when I tried to launch a new one after making some changes, they began fighting with each other. One making the changes I wanted, one then reapplying the default config and causing what seemed like a flicker. What I did was:

• alter settings via the ~/.config/redshift.conf file. (example here: http://jonls.dk/redshift/)
• kill the running redshift process(es) pgrep redshift | xargs -n1 kill -9
• restart redshift redshift-gtk & disown

You should see an icon in the upper right that looks like a light bulb that will allow control of reshift. And hopefully no more flickering!

Answer 2

If you are running Gnome or have updated to Ubuntu 18.04, then the Night Light feature may be conflicting with Redshift. Try disabling Night Light in Settings -> Displays.