The Big Sleep' (1946) starring Humphrey Bogart and Lauren Bacall is one of Raymond Chandler's best hard-boiled detective mysteries transformed in to a Film Noir, private detective film classic.
The Big Sleep is the best example of a classic Warner Brothers mystery. It is very complex, confusing
L.A. private eye Phillip Marlowe takes on a blackmail case and follows a trail peopled with murders, pornographers, nightclub rouges and the indulged rich. Humphrey Bogart plays Raymond Chandlers' legendary gumshoe and director Howard Hawks serves up quick paced character encounters mainly evolving Lauren Bacall, all set against an atmospheric background.
The genre that this film falls into is clearly defined as the category film noir. Film noir is translated as meaning "Black Film" this relates to the nature and ambience of the lighting. The lighting of the film is known as Chiaroscuro, Italian, meaning light and dark.
There are various conventions that are given to a film that make it fit the genre of film noir. It's almost exclusively set in a city environment, deals with corruption and vice as central storylines, the women are always problematic and are in essence dangerous. They also feature usually a private detective rather than a police officer as the detective doesn't represent the state and so therefore can bend the rules slightly but remain incorruptible. There are also many more primary moods of film noir, melancholy, alienation, bleakness, disillusionment, disenchantment, pessimism, ambiguity, moral corruption, evil, guilt and paranoia. Heroes or anti-heroes, corrupt characters and villains include down and out, hard boiled detectives or private eyes. These protagonists are often morally ambiguous low lifes from dark and gloomy underworld of violent crime and corruption.
The Big Sleep' fits in to all of the conventions