Originally Posted by LoathsomePete

It's this weird trend where genres are color coded. Horror movies seem to have a weird blue tint to them, post-apocalypse movies have a grey washed out look, movies set in desert locations have an orange tint, and ones that question reality have a green tint. It's been around for awhile but O Brother Where Art Thou used digital color correction to give it that old timey sepia tone, and other directors jumped on the technology because it was an easy way to create emotional responses in the audience without having to do any work. Also, blue and orange are on opposite ends of a color wheel so they contrast nicely.