> Perhaps the discomfort is just because of eyes having a hard time adjusting to noticeably different lighting conditions, but maybe there's more to it. Person

> Perhaps the discomfort is just because of eyes having a hard time adjusting to noticeably different lighting conditions, but maybe there's more to it. Personally I suspect it this. I’m not 100% of how exactly f.lux etc works, but I’ve always assumed they work by applying a full screen filter that basically just reduces the Blue channel values, and possibly tweaks the other channels a tad to keep things looking reasonable. Of course on of the side effects of doing that would be reducing the total amount of light your screen emits, and I assume this has to be true, because red and green would end up clipping if they were boosted to keep the light output the same. As the app applies removes more blue, it further dims the image, and when you turn it off if restores all the channels, which also increases the screens total light output. And you basically get the same effect as opening the curtains in the morning (assuming your working in darkish room), with the resulting eye discomfort while they adjust to the increased brightness. Best way to test this would be use the apps, and modulate the screen backlight to compensate for the reduced blue level, so the total lux emitted remains constant. Then switching back and forth would let you figure out is your eyes are responding to the blue, or just the total light level.