Save your eyes, use RedShift on linux and windows’ builtin night mode.
Redshift adjusts the color temperature according to the position of the sun. A different color temperature is set during night and daytime. During twilight and early morning, the color temperature transitions smoothly from night to daytime temperature to allow your eyes to slowly adapt. At night the color temperature should be set to match the lamps in your room. This is typically a low temperature at around 3000K-4000K (default is 3700K). During the day, the color temperature should match the light from outside, typically around 5500K-6500K (default is 5500K). The light has a higher temperature on an overcast day.
Use the config on the site if you encounter issues with the gtk applet. Or do if you don’t. :)
Set your location if redshift has issues retrieving it from the web with a 3 digit latitude and longitude value. I found mine by looking at the gtk applet’s info window when it did connect. OR you can use this url I found in the geoclue.conf file
If you want it to affect just one monitor; put this at the end of the config that site lists. Just omit the similar line listed on the site.