how does f.lux work?

Question

i am trying to figure out how this software works:

http://www.stereopsis.com/flux/

specifically, i would like to know how it changes the colors on your machine, and also was wondering if this would be possible to do in vb.net?

Answer 1

Most likely they play around with color management. Graphical operating systems allow for color calibration which changes the look of colors on a display. This is primarily used so the display has exactly the same color gamut as printers for design purposes or that the display has natural-looking colors. In this case it is used to adjust the color temperature programmatically.

In the FAQ they state "Currently, we don't recommend running f.lux on calibrated systems running Windows" which seems to reinforce the idea that they are messing with the color calibration (and are probably replacing the one you did previously).

Windows has support for this beginning with Vista and you probably can use this with VB.NET but not natively from .NET, meaning you will have to use the API directly. Here is an introduction about the Windows Color System on MSDN.

Note: Tried it out. Yes, they do mess with the color calibration. And they're pretty aggressive in that regard. Whenever I click "Reload current calibrations" in the color management panel to get my own calibration back (Windows 7 here) it gets reset by f.lux. It seems they are setting this about once a second. Now imagine there are two programs doing this :-)