Of course, not all period films sacrifice nuance for showiness. On Sunday, I'll be rooting for Walk the Line, because Arianne Phillips' costumes thoughtfully illuminate both the public personas and the private lives of two icons. It would have been easy enough to dress the Man in Black in black, but Phillips opted for a quiet tone. She also used surprising touches of authenticity: When someone who'd known Cash reported that the singer often wore khakis in the '50s, she decided to include a pair.