Experts say that the light that comes from the computer can affect your sleep cycles: “light emanating from the screen can also disrupt your body’s ability to prepare for sleep and literally wind down" F.lux is a small application for your computer to try to avoid this.

Working late at night with the computer could affect the sleeping cycles. Some lights affect the creation of serotonine that, among other things, regulates mood, appetite, sleep, muscle contraction, and some cognitive functions like memory and learning. Working with a computer and going directly to sleep may affect the quantity of serotonine that regulates your sleep, and give you problems for sleeping.

In the webpage of F.lux we can find some interesting studies about the quantity and quality of the light:

"These results suggest that low color temperature light creates a smooth lowering of central nervous system activity, and that low color temperature illumination can be used effectively in a bedroom or other such environment where it is desirable to facilitate lowered physiological activity." (Effect of Illuminance and Color Temperature on Lowering of Physiological Activity)

During the day the light in our surroundings changes but the light that comes from the computer screen doesn't. But it is not just about the quantity of light but also about the characteristic of this one. The computer screen light is designed to look like the sun's, with a lot of white light and a blue tones. During the night the regular bulb in our homes has a warmer quality with more orange tonality. This small program uses the time and latitude to adapt the light of your screen and to do some gamma correction to fix the color of it according to the light that surrounds you.

The software uses the latitude and time to know the quantity of light and it has the options for the kind of the light one has: Tungsten, Halogen, Fluorescent and Daylight. Its possible also to manually set the temperature of the screen.

F.lux comes for Windows and Mac OS X. Theres also a package for Linux (only for 24/32-bit displays) but doesn't have the graphic interface. Here are the instructions for an easy installation in Ubuntu.

This is not the only software to do this kind of thing with the screen.

• Redshift is a similar program for Linux.
• Nocture is the application for Mac
• Ambient light sensor for MacBooks Pro. This only measures the brightness of the light in your room and adjusts the brightness of your screen based on that. It doesn't make a color correction.

This software could be a help for the moment to go to sleep, but also to avoid to make our eyes working harder.