herf, i've been trying to find some info on this, but can you tell us why the default color settings changed so much? (recommended colors, vs. classic flux)
One answer is: because we could! Previously the setting you'd want right before bed looked totally silly at sunset.
But the more interesting answer is: we made a model after measuring dozens of panels with a spectrometer. The science isn't totally clear on this (it's clearer with super-bright lights), but it's our best read of what you actually need to wind down on a cross-section of current devices. Some of the new LED panels are pretty effective at stimulating melanopsin.
Overall, you can reduce a lot of circadian stimulus by dimming really far, but assuming you're working at a moderate level, you need pretty warm colors.
Really though, we can only do so much with displays, because if your lights are pretty bright in your bedroom, it doesn't matter what we do. So we'll probably have a large number of users choosing some less intense settings just because the room they're in doesn't match.
