Found footage refers to the filmmaking technique of using footage that was acquired (“found”) from pre-existing sources to create a new work such as a documentary, a video essay or essay film, a collage film or another work. (This same term has also come to denote an entire subgenre of horror movies, where the film is presented as consisting entirely or in part from footage that was recovered from or made by the characters in the film).
Using found footage is an example of appropriation. It is akin to the broader artistic concept of the objet trouvé: an object (either man-made or natural) that was found by chance and that was endowed with an aesthetic value by the finder, even though the object was not necessarily created as a piece of art. Think of the ready-made art pieces by Marcel Duchamp (his Fountain being the most famous, and endlessly cited, example).
Watch some examples of found footage essays from our best practices section.