Regarding the darkness at night, there are (it seems) two darkness settings for nighttime. There's the regular night that Konachibi linked a picture to earlier, and there's the "darker" night as well, which started happening back in May along with the Seventh Umbral Era event.

http://forum.square-enix.com/ffxiv/t...n-and-Coerthas!

As for the "constant dawn mist, like a white filter over the game world," it sounds like it's just fog, lol. My colors during the day--when the sun's out, mind you--are always nice and bright.