Hold on, brightness is not exactly the correct term here, f.lux allows you to adjust the screen’s color temperature, not just its intensity. Researchers believe the blueish light of a computer screen tricks your brain into thinking it is still day time. Shifting the color temperature to a more reddish hue is not only softer on your eyes, it can actually improve your sleep quality. This is especially helpful for nocturnal people like myself who often use the computer before going to sleep. And it’s quite cosy!
In fact it reminds of how much I hate these energy-saving light bulbs, especially the cheaper ones you can buy at Ikea. The old-fashioned incandescent light bulbs are banned from stores in Belgium for ecological reasons (not taking into account nasty chemicals like mercury involved in making energy-saving fluorescent lamps). I liked those so much better. Still have some spare ones, hee hee :p
As an experiment, install f.lux and do something useful like working on your latest code project for let’s say 10 minutes with the color temperature set to ‘halogen’ (3400K). Then switch it back to the default daylight setting (6500K). Holy toledo Batman, my eyes! Aaarghl!
I’ve started using f.lux during my daytime work as well, just slightly adjusting the temperature from the default 6500K to a slightly more mellow 5800K. Much nicer.
Highly recommended, check it out.