Black & White. It can be so more atmospheric than in colour. What's your favourite non-colour horror movie?
http://www.ranker.com/list/the-best-black-and-white-horror-movies/dee123,
Bride of Frankenstein
Dracula
Frankenstein
House on Haunted Hill
Night of the Living Dead
Psycho
The Bad Seed
The Haunting
The Invisible Man
The Night of the Hunter