Lost film
A film known to have existed but with no surviving copy currently known. Its status can change when a copy or fragment is discovered.
Nitrate film: A motion-picture film base made from cellulose nitrate, highly flammable and prone to chemical deterioration. Its instability and fire risk destroyed many films before preservation became systematic.
Vinegar syndrome: The chemical deterioration of cellulose acetate film, marked by acetic-acid odor, shrinkage, and brittleness. It can make a surviving safety-film copy unprojectable and eventually unusable.
The Passion of Joan of Arc: Carl Theodor Dreyer’s 1928 silent film depicting the trial of Joan of Arc. A nearly complete version was discovered in a Norwegian mental institution in 1981 after decades of scarcity.
Filmography: A complete or selected list of films associated with a person, company, or subject. Filmographies preserve evidence of works even when no copy can be viewed.
Film fragment: A surviving portion of a motion-picture work, shorter than a complete version. Fragments may be the only evidence of a film’s images or editing.
Silent film: A motion-picture film made during the era before synchronized recorded dialogue became standard. A large share of silent cinema has disappeared, making this era central to lost-film history.
Film decay: The physical and chemical deterioration of motion-picture film over time. Decay can turn a film from extant to effectively unavailable.
Metropolis: Fritz Lang’s 1927 science-fiction film about a sharply divided futuristic city. A long-missing Argentine print found in 2008 restored much of the footage absent from earlier versions.
Film cataloging: The description and organization of films and related archival materials. Catalog records can establish that a missing film existed and help locate overlooked copies.
Film provenance: The documented history of a film copy’s ownership, custody, and movement. Tracing provenance can connect an unidentified archival print to a supposedly lost title.