Chiaroscuro Lighting
Lighting a scene with strong contrast between bright light and deep shadow, a style borrowed from old paintings called chiaroscuro. How lit a character is hints at their moral or mental state.
The Maltese Falcon
Arthur Edeson's photography sets the look that film noir would copy: faces half in shadow, rooms lit by single lamps, venetian blind patterns on walls. This kind of strong light-and-dark contrast is called chiaroscuro. Every character in the film has a shadowed side, on screen and in their morals. I feel like the lighting is telling you that no one in this world is fully in the light, the detective included.
The Third Man
Krasker's photography gives Vienna its defining look: pools of lamplight on wet cobblestones and figures stepping out of doorway shadows. The black-and-white is pushed to such extremes that the city itself seems to be making a moral point. Harry Lime's reveal (the cat, the doorway shadow, the lamplight) is the most famous use of chiaroscuro, the strong contrast of light and dark, in film noir.

