Film Noir:

Film Examples:
Sunset Blvd.
The Letter
Double Indemnity

Visual Characteristics:
Long, irregular, verticle shadows cast upon the walls.
Elaborate "vanishing points" (points where characters enter or exit a scene)
Long plate glass windows with verticle blinds (that also sometimes serve to cast the shadows on the wall inside.

Narrative Characteristics:
sense of entrapment
complex plot
flashback