A silent film is a film with no synchronized recorded sound (and in particular, no spoken dialogue). In silent films for entertainment, dialogue is conveyed by the use of muted gestures and mime in conjunction with title cards, written indications of the plot and key dialogue lines. The idea of combining motion pictures with recorded sound is nearly as old as film itself, but because of the technical challenges involved, the introduction of synchronized dialogue became practical only in the late 1920s in film with the perfection of the Audion amplifier tube and the advent of the Vitaphone system. During the silent-film era that existed from the mid 1890s in film to the late 1920s, a pianist, theater organist—or even, in large cities, a small orchestra—would often play music to accompany the films. Pianists and organists would play either from sheet music, or improvisation.
The term silent film is a retronym—a term created to retroactively distinguish something. Early sound films, starting with The Jazz Singer in 1927, were variously referred to as the "talkies", "sound films", or "talking pictures". Within a decade, the widespread production of silent films for popular entertainment had ceased, and the industry had moved fully into the sound era, in which movies were accompanied by synchronized sound recordings of spoken dialogue, music and sound effects.
The vast majority of the silent films produced in the late 19th and early 20th centuries are considered lost. According to a September 2013 report published by the United States Library of Congress, some 70 per cent of American silent feature films fall into this category. There are numerous reasons for this number being so high; most were destroyed on purpose, but many others have been lost unintentionally. Out of a desire to free up storage space, film studios would often destroy silent films decades after their theatrical runs, perceiving them to have lost their cultural relevance and economic value. Due to the fragile nature of the nitrate film stock on which many silent films were recorded, many have deteriorated or have been lost in accidents such as fires (because nitrate is highly flammable and can spontaneously combust when stored improperly). Many such films not completely destroyed survive only partially, or in badly damaged prints. Some lost films, such as London After Midnight (1927), have been the subject of considerable interest by film collectors and historians.