ScreenBloom

ScreenBloom is a free PC/Mac application that grabs the average color of your screen and sends that value to connected Philips Hue lights.

ScreenBloom will run on just about anything, but the faster your CPU the better. While running ScreenBloom lives in ~16MB of RAM and uses ~3-15% of the CPU, with better CPUs being more efficient.

Each light adds another string of commands that the Hue bridge has to process before moving on to the next, so the fewer being addressed the more responsive ScreenBloom will be. To address more than 2 bulbs at once, set a small (0.1s) Update Buffer. This tiny pause will be undetectable to you but will give your bridge enough time to comfortably process all the commands being thrown at it.