Signifiers of Masculinity
As with most noir, the central protagonist in The Big Sleep is a hard-boiled detective, who knows how to get the job done, all the while exhibiting traditionally macho and masculine qualities. Humphrey Bogart as Philip Marlowe is the quintessential example of this. He is nearly always wearing a fedora cocked at a slight angle, smoking cigarettes, and drinking heavily, an outlaw who works for the good of society. His apartment and his offices are stark, Spartan rooms, far from the reach of a more aesthetic feminine touch. He is the consummate lone wolf and bachelor, sporting a trench coat and flirting with every woman in sight. Additionally, Humphrey Bogart's face itself is a kind of craggy marvel of masculine no-nonsense. While he tries on expressivity at times, it is always sarcastic, and his neutral expression is either seriously straight-faced, or knowingly smirking. Philip Marlowe is the image of a kind of stereotypical mid-century American masculinity, all virile gristle and no-nonsense ruggedness.
Nymphomania & Uncontrolled Sexuality
In the book, Carmen Sternwood is beyond all question a highly sexed nymphomaniac, but a film made in the 1940s had to comply with a conservative Hays Code, and could hardly be faithful to such a description. Still, Hawks managed to include many aesthetic hints at the compulsive darkness behind Carmen's sexuality. Carmen is introduced to both Marlowe and the viewer in a highly provocative outfit: extremely high shorts that look more like a skirt and showcase her long legs. Additionally, she coquettishly adjusts her hair, bites her thumb, and flirts outrageously with the middle-aged Marlowe. She is a walking pin-up, completely indiscreet and unmeasured in her sensual gestures, which does a lot to show her pathologically proportioned erotic desires. The collective imagery of Carmen provides a fairly accurate portrait of the wayward girl, who was more explicitly described in the novel.
Shadows and Silhouettes
As in most noir, shadows and light are employed throughout to heighten suspense and add more mystery to the plot of the movie. When Marlowe arrives at Geiger's house, it is dark and he can hardly see anything, but waits in his car patiently for something to happen. A single light brightens the window of the house. When he follows the sound of the gunshot into the house, he finds the room dark and forbidding. A drugged Carmen sits in a chair in a robe, and it is clear that something not-so-savory has been taking place. The relative darkness of the house represents the darker morals of Geiger and his accomplices. Marlowe must "shine a light" on the truth of the matter.
Later, when Marlowe visits the room to get the information from Agnes, he hears Canino and Harry Jones arguing in the room, and hides behind a wall to listen in. There, he sees Jones in silhouette behind the wall being grilled by Canino. The shadows are theatrical and highlight that Marlowe is very close to the truth, but also distanced from it to some extent. He must hide out and listen in in order to discover what is actually going on. The silhouette represents his simultaneous proximity to and distance from the truth.
The Hothouse
In the first scene of the film, Marlowe is led into a heated greenhouse at the Sternwood residence. The heat of the room keeps the old man, Sternwood, alive. While Sternwood spends time in the heat under the advisement of a doctor, it causes Marlowe to sweat profusely as he learns more about the mystery he is to solve. The contrast between General Sternwood, placidly wrapped in blankets in the heat, and Marlowe, who struggles to stay cool in the balmy environment, represents their distance from one another in society and the strange world that Marlowe will have to traverse. The greenhouse is where we learn the central premise of the film, and where we are tipped off to the unusual proportions of the story. The greenhouse itself is an eccentric environment—filled with a motley array of living things, vines, tropical flowers, and botanical oddities—foreshadowing the strange course of events that will take place.
