Not a movie but a genre. Film noir is a style and mood primarily associated with crime films, that portrays its principal characters in a nihilistic and existential world. Film noir is primarily derived from the hard-boiled style of crime fiction of the Depression era, (many films noir were adaptations of such novels), and may first be clearly seen in films released in the early 1940s. 'Noirs' were historically made in black and white, and had a dark, high-contrast, style with roots in German Expressionist cinematography.
Noir films, traditionally black and white, tended to include dramatic shadows and stark contrast—using low-key lighting and monochrome film, typically resulting in a 10:1 ratio of dark to light, rather than the more typical 3:1 ratio. Noir is also known for its use of dutch angles, low-angle shots, and wide angle lenses. A number of noir films were shot on location in cities, and night-for-night shooting was common. Also common to be seen in any noir film are shadows of venetian blinds. These are dramatically cast upon an actor's face as he looks out a window. This is one of the many iconic visuals in noir.
Film noir tends to revolve around flawed and desperate characters in an unforgiving world. Crime, usually murder, is an element of all films noir, often sparked by jealousy, corruption, or greed. Most films noir contain certain archetypal characters (such as hardboiled detectives, femmes fatales, corrupt policemen, jealous husbands, insurance agents, or down-and-out writers), familiar locations (downtown Los Angeles, New York, or San Francisco), and archetypal storylines (heist films, detective stories, court films, and films about rigged boxing games).
Film noir is at its core pessimistic. The stories it tells are of people trapped in a situation they did not want, often a situation they did not create, striving against random uncaring fate, and usually doomed. Almost all film noir plots involve the hard-boiled, disillusioned male and the dangerous femme fatale.
Many of the classic noir films were low-budget supporting features without major stars, in which 'moonlighting' writers, directors and technicians, some of them blacklisted, found themselves relatively free from big-picture restraints. Many of the most popular examples of film noir center upon a woman of questionable virtue and are also known as bad girl movies. Major studio feature films demanded a wholesome, positive message. Weak and morally ambiguous lead characters were ruled out by the "star system", and secondary characters were seldom allowed any depth or autonomy. In "A" films, flattering soft lighting, deluxe interiors and elaborately-built exterior sets were the rule. Noir turned all this on its head, creating bleak but intelligent dramas tinged with nihilism, mistrust, bleakness, paranoia and cynicism, in real-life urban settings, and using unsettling techniques such as the confessional voice-over or hero's-eye-view camerawork. Gradually the noir style re-influenced the mainstream.