A lot of the scenes had lighting as seen above. Drastic shadows (on the right), and limited light (on left).This type of lighting leaves a ton to the imagination, and contrast is naturally appealing to the eye.
A similar theme was seen in Chinatown, although the Noir elements are less obvious in this movie. I the very beginning, the P.I made a reference to “Venetian blinds”. Which I though was pretty clever of them