Collage film is a style of film created by juxtaposing found footage from disparate sources. The term has also been applied to the physical collaging of materials onto film stock.

Surrealist roots of collage film
The surrealist movement played a critical role in the creation of the collage film form. In 1936, the American artist Joseph Cornell produced one of the earliest collage films with his reassembly of East of Borneo (1931), combined with pieces of other films, into a new work he titled Rose Hobart after the leading actress. When Salvador Dalí saw the film, he was famously enraged, believing Cornell had stolen the idea from his thoughts. But Adrian Brunel made, twelve years before, Crossing the Great Sagrada (1924) and Henri Storck conceived, four years earlier, Story of the Unknown soldier (Histoire du soldat inconnu) (1932.)

The idea of combining film from various sources also appealed to another surrealist artist André Breton. In the town of Nantes, he and friend Jacques Vaché would travel from one movie theater to another, without ever staying for an entire film.

Renaissance
A renaissance of found footage films emerged after Bruce Conner’s A Movie (1958). The film mixes ephemeral film clips in a dialectical montage. A famous sequence made up of disparate clips shows “a submarine captain [who] seems to see a scantily dressed woman through his periscope and responds by firing a torpedo which produces a nuclear explosion followed by huge waves ridden by surfboard riders.” Conner continued to produce several other found footage films including Report and Crossroads among others.

Working at the National Film Board of Canada (NFB) in the 1960s, Arthur Lipsett created collage films such as Very Nice, Very Nice (1961) and 21-87 (1963), entirely composed of found footage discarded during the editing of other films (the former earning an Academy Award nomination).

In 1968, the young Joe Dante made The Movie Orgy with producer Jon Davidson that featured outtakes, trailers and commercials from various shows and films.

Recent examples
Other notable users of this technique are Craig Baldwin in his films Spectors of the Spectrum, Tribulation 99 and O No Coronado. Bill Morrisson uses found footage lost and neglected in film archives in his 2002 work Decasia (which alongside Kevin Rafferty’s 1982 Cold War satire The Atomic Cafe were inducted to the National Film Registry). A similar entry in the found footage canon is Peter Delpeut’s Lyrical Nitrate (1991).

The technique was employed in the 2008 feature film The Memories of Angels, a visual ode to Montreal composed of stock footage from over 120 NFB films from the 1950s and 1960s. Terence Davies used a similar technique to create Of Time and the City, recalling his life growing up in Liverpool in the 1950s and 1960s, using newsreel and documentary footage supplemented by his own commentary voiceover and contemporaneous and classical music soundtracks.

The 2016 experimental documentary Fraud was sourced from over a hundred hours of home video footage uploaded to YouTube by an unknown family in the United States. The footage was collaged with additional clips appropriated from other YouTube users and transformed into a 53-minute crime film about a family preoccupied with material consumption going to extreme lengths in order to get out from under unsustainable personal debt.

Comedies
Some of the earliest surrealist collage works were humorous. This tradition of using film collage for comedic effect can later be seen in commercial films such as Woody Allen’s first film, What’s Up, Tiger Lily? in which Allen took a Japanese spy film by Senkichi Taniguchi, re-edited parts of it and wrote a new soundtrack made up of his own dialogue for comic effect, and Carl Reiner’s 1982 comedy Dead Men Don’t Wear Plaid which incorporated footage from approximately two dozen classic film noir films along with original sequences with Steve Martin.

Physical film collaging
Some filmmakers have taken a more literal approach to collage film. Stan Brakhage created films by collaging found objects between clear film stock, then passing the results through an optical printer, such as in Mothlight and The Garden of Earthly Delights.

Animation
Examples of animated collage film (which uses clippings from newspapers, comics and magazines alongside other inanimate objects):

The Oscar-winning Frank Film
Our Lady of the Sphere
The films of Lewis Klahr and Janie Geiser
Charles Braverman’s American Time Capsule
Heaven and Earth Magic
The works of Stan Vanderbeek and Robert Breer
The aforementioned Mothlight and The Garden of Earthly Delights

Source from Wikipedia