Donnie Darko - symbolic uses of light and darkness

A disturbing fantasy thriller from Richard Kelly, Donnie Darko is the story of a brilliant but troubled teennager who becomes immersed in a series of bizarre events that may or may not be real.
     The teenager, Donnie Darko, begins to have visions where Frank, a man in a demented looking rabbit costume, tells him that the world will end in 28 days. In each further appearance, Frank urges him to commit various acts of vandalism because "he can't get caught". He also lectures him about time travel, adding to his confusion. Donnie's attempt to unravel the meaning of his visions and avert the end of the world are the central plot of this movie, which is a sci-fi update of the film noir classics of the 1940's. In common with such films as Double Indemnity, Donnie Darko uses light and darkness to symbolize elements of the film and the characters in it. Whenever Frank appears, the surroundings seem to dim with the only light on him, symbolizing the fact that he seems to exist in a world that only Donnie can see. His appearances are also dark in the sense that they usually precede something bad happening. The opposite is true when Gretchen, his love interest, appears - most of the scenes are brighter, symbolizing the hope and optimism he feels around her. The film uses both light and darkness not only to set the tone of the film, which is basically pessimistic (and paranoid), but also to symbolize the uncertainty about what is actually going on. We are never completely sure if the events of the movie are actually occurring due to time travel paradoxes or if they exist only in the main character's head.
     I gave this movie a thumbs up, even though I was never completely sure of what was really happening in it. The " what is reality" theme was actually the movie's strong point, giving it an aspect that some other films of this type don't have.