8mm is a 1999 American mystery thriller film, directed by Joel Schumacher and written by Andrew Kevin Walker. It stars Nicolas Cage as a private investigator who delves into the world of snuff films.

Private investigator Tom Welles is contacted by Daniel Longdale, attorney for wealthy widow Mrs. Christian, whose husband has recently died. While clearing out her late husband's safe, she and Mr. Longdale find an 8 mm film which appears to depict a real murder, but Mrs. Christian wants to know for certain.

After looking through missing persons files, Welles discovers the girl is Mary Ann Mathews, and visits her mother, Janet Mathews. While searching the house with her permission, he finds Mary Ann's diary, in which she says she went to Hollywood to become a film star. He asks Mrs. Mathews if she wants to know the truth, even if it is the worst. She says that she wants to know what happened to her daughter.

In Hollywood, with the help of an adult video store employee called Max California, Welles penetrates the underworld of illegal pornography. Contact with a sleazy talent scout named Eddie Poole leads them to director Dino Velvet, whose violent pornographic films star a masked man known as "Machine." To gain more evidence, Welles pretends to be a client interested in commissioning a hardcore bondage film to be directed by Velvet and starring Machine. Velvet agrees and arranges a meeting in New York City.

A film, also called a movie or motion picture, is a series of still or moving images. It is produced by recording photographic images with cameras, or by creating images using animation techniques or visual effects. The process of filmmaking has developed into an art form and industry.

Films are cultural artifacts created by specific cultures, which reflect those cultures, and, in turn, affect them. Film is considered to be an important art form, a source of popular entertainment and a powerful method for educating – or indoctrinating – citizens. The visual elements of cinema give motion pictures a universal power of communication. Some films have become popular worldwide attractions by using dubbing or subtitles that translate the dialogue into the language of the viewer.

Films are made up of a series of individual images called frames. When these images are shown rapidly in succession, a viewer has the illusion that motion is occurring. The viewer cannot see the flickering between frames due to an effect known as persistence of vision, whereby the eye retains a visual image for a fraction of a second after the source has been removed. Viewers perceive motion due to a psychological effect called beta movement.