 According to costume designer Edith Head (qv)s biography, Redford  and Newman, both of whom have blue eyes, wanted their shirts to be  blue in order to emphasize their eyes. As a compromise, Head  outfitted each man in blue in alternating scenes. Unfortunately,  although it is an attractive story, its a complete myth. A simple  viewing of the film reveals the truth. Newman is never outfitted in  blue in the whole film. He is first seen in a white vest in the  brothel scenes. On the train he alternates between a brown striped  shirt and a white one, which may or may not be a continuity error.  From then until the end of the film, he is seen exclusively in a  dinner jacket and white shirt. Redford wears a blue shirt on a  couple of occasions, but even this doesnt really fit with this  oddly persistent legend.