Night light and Redshift don't work

I installed Ubuntu on a disk partition just two days ago and everything work like a charm. The only problem I'm having is with the screen temperature color. In Windows I use f.lux and I set the color temperature as red as possible (3500K) all-day-long. I want to do the same in Ubuntu but I faced many issues:

• f.lux doesn't change the color at all
• Redshift changes the temperature for a couple of seconds, then it suddenly goes back to the normal color
• GNOME Night Light has the same problem of Redshift: the change is not permanent although I set the color temperature to be 3500K from 5AM to 3AM

Is anyone having the same problem? How can I fix it?

System info:

• Ubuntu 18.04.1 LTS
• GNOME 3.28.2
• External monitor HP 24" 60,00 Hz

Solution 1:

I found that for Night Light I have to set it to manual mode and set the start time to some time before the current time and the end time sometime before the end time.

I was perplexed for a while because I assumed that, like all other widgets in Ubuntu, setting the switch to on (green) would just turn Night Light on.

Solution 2:

Try un-installing redshift, then use a night light.

I was also having some issues with redshift, couldn't get it to work. So then I tried night light - the colour temperature would flash on for a second and then off again...periodically.

I think there might have been a conflict with redshift, because after I uninstalled it from the command line with

sudo apt-get remove redshift

then the colour temperature on night light seemed to work as expected.