To begin to appreciate the ways in which lighting can shape the ways we respond to a film, consider the scene in Alfred Hitchcock's Suspicion (1941) where a young wife (Joan Fontaine) lies ailing in her bed while her mysterious newlywed husband (Cary Grant) slowly ascends the stairs to her room, advancing through a spiderweb of foreboding shadows. On a small tray he carries a glass of milk that glows with an eerie luminosity. The scene invites us to wonder whether he might be trying to poison his wife. Such mistrust assuredly does not arise from the popular actor's star image; instead, the ominous shadows cast across the set and the covert placement of a light bulb inside the glass combine to arouse unease.
Lighting has come to be an important component of cinema's visual design. It is widely recognized that in film, as elsewhere, it can create a substantial emotional impact. A primordial response to darkness and light is a deep-seated element of human psychology that filmmakers have harnessed in order to influence the ways viewers respond to narrative development. On the one hand, deep shadows can make a character seem untrustworthy or conceal a host of horrors. On the other, bright, diffused lighting can provide comfort and reassurance or create the impression of an angelic countenance. Extremely bright light can cause discomfort, though, and can even be used as a weapon, as in Rear Window (1954) and The Big Combo (1955), where it dazzles the villains and halts their advance.
Brightness is only one variable of lighting that can contribute to the effect of a scene. The choices the cinematographer makes about what kinds of lights will be used, how many there will be, and where they will be placed all require careful consideration. Moreover, color and black-and-white cinematography each allows for different lighting effects. Colored lighting can give rise to a range of subjective impressions that may be systematically used throughout a film for atmosphere, as in the moody and heavily stylized Batman (1989), or for metaphorical significance, as in Vertigo (1958) when Scottie (James Stewart) persuades Judy (Kim Novak) to transform her appearance into that of the dead Madeleine (Novak). When she emerges from her bathroom made over into Madeleine's image, she is bathed in a green light, its supernatural associations accentuating the uncanniness of the resurrection of her alter ego.
Film lighting has three main purposes. The first is clarity of image. It is important for viewers to be able to discern all the important elements in the frame. These might range from facial expressions and physical gestures to the presence of significant props. In early cinema this was the sole purpose of lighting, but around 1905 other factors came into play. Lighting's second purpose is a quest for greater realism. Films began to introduce visual schemes that suggested that the lighting came from logical sources within the world depicted. The use of "effects lighting," as it was known at the time, paved the way for the third purpose: the creation of atmosphere or emotional effect. The development of lighting technique as a significant element of mise-en-scène became an important tool for manipulating audience responses to characters and narrative events. Increasingly, a repertoire of standardized lighting techniques came to be used for particular dramatic situations and particular lighting styles came to be strongly associated with film genres.