The theory behind F.lux is simple and the execution, in its simplicity, is beautiful. F.lux is designed with the thought “maybe we shouldn’t be staring at the blinding sun all day and night.” It adjusts the brightness of your monitor automatically according to the time of day. So during the day, it reaches full brightness at noon and after it crosses 6PM the light starts to get a warm, orange glow and looks less like a fluorescent light bulb. Many people have reported that using F.lux has improved their ability to sleep right after using the computer since the monitor no longer looks like the noon day sun.
The nice part is that F.lux works perfectly on its own in the background, tucked away in a system tray icon. It uses less than 4 MB of RAM while running and will adjust the monitor lighting as needed based on time of day. The only thing I’ve seen as downsides include A) It didn’t work inside a VM and B) it may have slowed down the computer a bit while it was adjusting the lighting. This last problem is a little hard to confirm and I haven’t seen it repeated.
Under settings, you can change your location and the maximum dimness and brightness the monitor should reach at midnight and noon, respectively. You can also how quickly you’d like the transition to take place over 20 seconds or over 60 minutes.
There are two convenient settings that ease the adoption of F.lux. If you open up the system tray icon, you’ll see the first window above where the dot tells you what part of the day it is. If you click that dot, it will give you a quick cycle through the 24 hours to show you how your colors will look. This is very useful for figuring out how exactly you want the settings to be configured. F.lux also includes the ability to disable the lighting change for 1 hour in case you need to see the true colors. I noticed this just with taking screenshots, the colors can change drastically. Since the softer lighting is changed on the monitor and not how the OS renders colors, screenshots will remain their true color. This is also the reason why I wasn’t able to take a picture to show how the picture is softened. I guess, you’ll just have to try F.lux for yourself.
I have a LCD monitor and a CRT monitor in a dual-monitor configuration and I notice the lighting having a much more significant effect on the LCD. While others have reported better sleeping patterns, I have noticed at the very least not being quite so blinded and less eye strain upon first looking at the monitor in the dark evening.
An alternative for those on Linux: Redshift