On Psycho -- comparatively late Hitch, 1960 when he was well into colour; but he deliberately made it in retro-b&w explicitly to underline its 'noir' aspects.

[Spielberg much later [1990s] did same thing re Schindler's List, where the little girl's red coat is the only splash of effective colour thruout. {All in all a terrible exploitative film I thought that, & a grave disappointment; but the point remains}.]

~M~