The Maltese Falcon touches on every usual part of film noir lighting. Most rooms are only lit by one or two lamps, the streets of the city are dark with the exception of a part of the character’s face being illuminated, and shadows are cleverly cast across faces. In the image above, Mrs. O’Shaughnessy’s path towards indictment begins with her entering the elevator in Sam’s apartment building. After she enters the elevator, the bars cast “prison bars” across her face, signaling her eventual imprisonment.
The image above comes from the beginning of the film. Sam is much more open and willing to take customers at the beginning of the film, before he gets wrapped up in the murder of his partner. Sam seems trustworthy and much more straightforward at the beginning. This is displayed through his completely illuminated face, with the light reaching across most of his face.
In contrast, the image below shows Sam’s want to lay low and get out of his current problem. Contrasting his openness and highly illuminated face in the beginning of the movie, Sam’s eyes are covered up by the shadow cast by his hat. Sam can no longer be trusted, by his colleagues and the audience alike. As the eyes are the windows to the soul, Sam wants to hide any hints that may result from his looks.