Adaptation introduces complications in audience perception and aesthetics. The most obvious and common form of film adaptation is the use of a novel as the basis of a film, but film adaptation includes the use of non-fiction (including journalism), autobiography, comic book, scripture, plays, and even other films. From the earliest days of cinema, adaptation has been nearly as common as the development of original screenplays.
Novel adaptations and fidelity
Novels are frequently adapted for films. For the most part, these adaptations attempt either to appeal to an existing commercial audience (the adaptation of best sellers and the "prestige" adaptation of works) or to tap into the innovation and novelty of a less well known author. Inevitably, the question of "faithfulness" arises, and the more high profile the source novel, the more insistent are the questions of fidelity.
Elision and interpolation
Erich von Stroheim attempted a literal adaptation of Frank Norris's novel McTeague in 1924 with his film, Greed. The resulting film was over sixteen hours long. A cut of the film only eight hours long, then one running to four hours, appeared. Finally, the studio itself cut the film to around two hours, resulting in a finished product that was entirely incoherent. Since that time, few directors have been foolish enough to attempt to put everything in a novel into a film. Therefore, elision is nearly mandatory.
In some cases, however, film adaptations will also interpolate scenes or invent characters. This is especially true when a novel is part of a literary saga. Incidents or quotes from later or earlier novels will be inserted into a single film. Additionally, and far more controversially, film makers will invent new characters or create stories that were not present in the source material at all. Given the anticipated audience for a film, the screenwriter, director, or movie studio may wish to increase character time or invent new characters. For example, William Kennedy's Pulitzer Prize winning novel, Ironweed, had a very small section with a prostitute named Helen. Because the movie studio anticipated a female audience for the film and had Meryl Streep for the role, Helen became a significant part of the film. However, characters are also sometimes invented to provide the narrative voice.
As Sergei Eisenstein pointed out in his landmark essay on Charles Dickens ("Dickens, Griffith, and the Film Today", Film Form), films most readily adapt novels with externalities and physical description: they fare poorly when they attempt the Modern novel and any fiction that has internal monologue or, worse, stream of consciousness. When source novels have exposition or digressions from the author's own voice, a film adaptation may create a commenting, chorus-like character to provide what could not be filmed otherwise. Thus, in the adaptation of John Fowles's The French Lieutenant's Woman, the director created a contemporary Englishman in a romance with a woman to offer up the ironic and scholarly voice that Fowles provided in the novel, and the film version of Laurence Sterne's "unfilmable" novel, Tristram Shandy had the main actor speak in his own voice, as an actor, to emulate the narrator's ironic and metafictional voice in the novel. Early on, film makers would rely upon voice over for a main character's thoughts, but, while some films (e.g. Blade Runner) may self-consciously invoke the older era of film by the use of voice over, such devices have been used less and less with time.
There have been several nominees for non plus ultra of inventive adaptation, including the Roland Joffe adaptation of The Scarlet Letter with explicit sex between Hester Prynn and the minister and Native American attacks on Salem (changes introduced, according to Joffe, to increase the market and to make an entirely new morality tale out of the novel). At nearly the same time, Daniel Defoe's Moll Flanders was creatively adapted to make it a romance. A television mini-series of Gulliver's Travels changed the sexes of characters, made some vanish, and changed the character of Master Bates from a single 3 sentence obscene pun into a villain. The Charlie Kaufman and "Donald Kaufman" penned Adaptation was an intentional satire and commentary on the process of film adaptation itself. All of these cases of "outrageous" or "unfaithful" adaptation were interpretations of the source work. Joffe argued that his changes were a recasting and revitalizing of Hawthorne's point. The creators of the Gulliver miniseries interpolated a sanity trial to reflect the ongoing scholarly debate over whether or not Gulliver himself is sane at the conclusion of Book IV. In these cases, adaptation is a form of criticism and recreation, as well as translation.
Change in adaptation is essential and practically unavoidable, mandated both by the constraints of time and medium, but how much is always a balance. Some film theorists have argued that a director should be entirely unconcerned with the source, as a novel is a novel, while a film is a film, and the two works of art must be seen as separate entities. Since a transcription of a novel into film is impossible, even holding up a goal of "accuracy" is absurd. Others argue that what a film adaptation does is change to fit (literally, adapt), and the film must be accurate to either the effect (aesthetics) of a novel or the theme of the novel or the message of the novel and that the film maker must introduce changes where necessary to fit the demands of time and to maximize faithfulness along one of these axes.
In addition to adaptation from novels, films frequently use plays as their sources. William Shakespeare has been called the most popular screenwriter in Hollywood. Not only are there film versions of all of Shakespeare's plays, but there are multiple versions of many of them, and there are films adapted from Shakespeare's plays very loosely (such as West Side Story, Kiss Me Kate, O, and 10 Things I Hate about You, as well as Akira Kurosawa's adaptations in Throne of Blood and Ran). Similarly, hit Broadway plays are frequently adapted, whether from musicals or dramas. On the one hand, theatrical adaptation does not involve as many interpolations or elisions as novel adaptation, but, on the other, the demands of scenery and possibilities of motion frequently entail changes from one medium to the other. Film critics will often mention if an adapted play has a static camera or emulates a proscenium arch. Laurence Olivier consciously imitated the arch with his Henry V (1944), having the camera begin to move and to use color stock after the prologue, indicating the passage from physical to imaginative space. Sometimes, the adaptive process can continue after one translation. Mel Brooks's The Producers was a film that was adapted into a Broadway musical and then adapted again into a film.
Television and other theatrical adaptation
Feature films are occasionally created as a full and (usually) uncensored version of a television series or television segments. In these cases, the film will either offer a longer storyline than the usual television program's format or will offer a greater set of production values. In the adaptation of The X Files to film, for example, greater effects and a longer plotline were involved. Additionally, adaptations of television shows will offer the viewer the opportunity to see the television show's characters without broadcast restrictions. These additions (nudity, profanity, explicit drug use, explicit violence) are only rarely a featured adaptive addition (film versions of "procedurals" such as Miami Vice are most inclined to such additions as featured adaptations). Because the film makers are adapting established characters with expected behaviors, introducing obviously non-broadcast elements may alienate a core audience, and therefore nudity, drug use, and violence for the main characters may be increased from broadcast standards, but they are unlikely to be a significant film element. Instead, films will try to offer a "real" story, as if commercial television were inherently censored for complexity. Some adaptations of television shows are nostalgic and usually ironic. Films about television shows of the audience's childhood (e.g. Scooby-Doo) play up television conventions and will sometimes exploit the distinction between movie and television possibilities for comedic effect.
At the same time, some theatrically released films are adaptations of television mini-series events. When national film boards and state controlled television networks co-exist, film makers can sometimes create very long films for television that they may adapt solely for time for theatrical release. Both Ingmar Bergman (notably with Fanny and Alexander, but with other films as well) and Lars von Trier have created long television films that they then recut for international distribution.
Even segments of television shows have been adapted into feature films. The American television variety show Saturday Night Live has been the origin of a number of films, beginning with The Blues Brothers, which began as a one-off performance by Dan Aykroyd and John Belushi. The most recent of these Saturday Night Live originated films is a case of double television origin: Fat Albert, which began with an impression of another television show based on the comedy routine of Bill Cosby. Rowan Atkinson has starred in three British films that originated on television: Mr. Bean, Johnny English, and Mr. Bean's Holiday.
Radio narratives have also provided the basis of film adaptation. The Hitchhiker's Guide to the Galaxy, for example, began as a radio series for the BBC and then became a novel which was adapted to film. In the heyday of radio, radio segments, like television segments today, translated to film on several occasions, usually as shorts. Dialog-heavy stories and fantastic stories from radio also adapted to film (e.g. Fibber McGee, Life with Father and Superman, which was a serial on radio before being adapted to film).
Comic book characters, particularly superheroes, have long been adapted into film, beginning in the 1940s with Saturday movie serials aimed at children. Superman (1978) and Batman (1989) are two later successful movie adaptations of famous comic book characters. In the early 2000s, blockbusters such as X-Men (2000) and Spider-Man (2002) ) have led to dozens of superhero films. The success of these films has also led to other comic books not necessarily about superheroes being adapted for the big screen, such as Ghost World (2001), American Splendor (2003) and Sin City (2005).
The adaptation process for comics is different from that of novels. Many successful comic book series last for several decades and have featured several variations of the characters in that time. Films based on such series usually try to capture the back story and “spirit” of the character instead of adapting a particular storyline. Occasionally aspects of the characters and their origins are simplified or modernized.
Self-contained graphic novels, many of which do not feature superheroes, can be adapted more directly, such as in the case of Road to Perdition (2002) and V for Vendetta (2006). In particular, Robert Rodriguez did not use a screenplay for Sin City but utilized actual panels from writer/artist Frank Miller's series as storyboards to create what Rodriguez regards as a "translation" rather than an adaptation.
Furthermore, some films based on long-running franchises use particular storylines from the franchise as a basis for a plot. The second X-Men film was loosely based on the graphic novel X-Men: God Loves, Man Kills and the third film on the storyline Dark Phoenix Saga.
Adaptations from other sources
Documentary films have been made from reportage, as have dramatic films (e.g. All the President's Men, and, most recently, Miracle (film), which was adapted from a deadline written book after the 1980 "miracle on ice"). An Inconvenient Truth is Al Gore's documentary film about climate change. It is a film adaptation of a Keynote multimedia presentation and is an adaptation, therefore, of a lecture. Some films have been made based on photographs (e.g. Pretty Baby, directed by Louis Malle), and movies have adapted movies (e.g. Twelve Monkeys deriving from La Jetée). Many films have been made from epic poetry. Homer's works have been adapted multiple times in several nations. Finally, both Greek mythology and the Bible have been adapted frequently. In these cases, the audience already knows the story well, and so the adaptation will de-emphasize elements of suspense and concentrate instead on detail and phrasing. The specifics of the acting take precedence over cinematic techniques.
Popular films have been adapted into both novels and plays. Many movie studios commission novelizations of their popular titles or sell the rights to their titles to publishing houses. These novelized films will frequently be written on assignment (i.e. hack writing), and will sometimes be written by authors who have only an early script as their source. Consequently, novelizations are quite often changed from the films as they appear in theaters. These differences are not, properly speaking, adaptations, but rather accidents of production. Further, novelization authors can frequently use the extended time available on the printed page to build up characters and incidents for commercial reasons (e.g. to market a card or computer game, to promote the publisher's "saga" of novels, or to create continuity between films in a series); these are introductions of alien matter rather than adaptations necessitated by form. There have been, however, a few instances of novelists who have worked from their own screenplays to create novels at nearly the same time as a film. Both Arthur C. Clarke, with 2001: A Space Odyssey, and Graham Greene, with The Third Man, have worked from their own film ideas to a novel form (although it is worth noting that the novel version of The Third Man was written more to aid in the development of the screenplay than for the purposes of being released as a novel, and that 2001's novelization was written in parallel with the screenplay). Both John Sayles and Ingmar Bergman write their film ideas as novels before they begin producing them as films, although neither director has allowed these prose treatments to be published.
Finally, films have inspired and been adapted into plays. John Waters's films have been successfully mounted as plays; both Hairspray and Cry Baby have been adapted, and other films have spurred subsequent theatrical adaptations. The most recent incidence of this is Spamalot, which is a Broadway play based on Monty Python films. In a rare case of a film being adapted from a stage musical adaptation of a film, in 2005 the film adaptation of the stage musical based on Mel Brook's classic comedy film The Producers was released.
Other adaptive processes
Although not truly a case of artistic adaptation, there have been rare examples of films inspiring or creating religions, such as the new emphasis on Jedi religion coming from the Star Wars films, which themselves adapted other films (notably The Hidden Fortress). Also, films have inspired and been adapted into journalism (e.g. The Thin Blue Line inspired journalistic investigations resulting in the freeing of a death row inmate, and Harlan County, USA inspired investigative reports that aided in labor conflict resolution in the US).
Eisenstein, Sergei. "Dickens, Griffith, and the Film Today." Film Form Dennis Dobson, trans. 1951.
The History of Erich von Stroheim's Greed.