If you like to sit up late staring at a computer screen in the dark, or you live with people who do, then you may have noticed how strangely blue the glow of the screen seems to be.
What seems perfectly normal under general lighting suddenly looks cold and sterile. That's because computer screens not only have brightness, but they are also set to a certain colour temperature — and the standard temperature setting is full daylight. Daylight seems weird late at night, so if you'd prefer to bring your colour temperature down to something warmer there is a great little application called F.lux.
Set your preferred daytime and night-time colour temperature, and F.lux will watch the clock and adjust your screen to suit.