From The Hobbit blog about 3D with Peter Jackson:

http://www.youtube.com/watch?v=gHF536TJ0iE
mentions of coloring begin @ 5:41

Peter Jackson: "If you look at the ungraded footage, the trees look incredibly psychedelic. They look like they were painted in 1967. In the movie, they won't look anything like that. They'll be graded down and you'll just get the barest hint of color in the finished film."

Prosthetics Superior: "we have to change our whole way about coloring these things, 'cause we found out in early tests that if there wasn't enough red in the pieces they would punch-up yellow and react differently than normal skin with blood running through it"

Frankly, all this sounds like they are "laboring under a misconception", unless their state-of-the-art cameras are "color challenged". Even so, there still is no excuse for green-tint clouds or, worse green-tint titles ... here, or in any of TLOTR movies:

http://www.cheapassgamer.com/topic/295388-lord-of-the-rings-extended-edition-trilogy-6585-fs/#entry9847547