Part of the film

In the USSR , as in most countries, the length of one part of a 35 mm film was set to 295 meters (with a lower limit of 250 meters and a length of the last part of at least 140 meters) ^{[2] [1]} . The standard length of a part of a wide-format film on a 70-mm film reaches 350 meters, having approximately the same duration on the screen as part of a 35-mm copy. In the footage part includes the length of the initial and final standard leader tape . The length of the leader tape of one part of a 35 mm film is 4.05 m, the widescreen one is 6.9 m. With a sound movie projection frequency of 24 frames per second, the standard part of a 35 mm and 70 mm film lasts about 10 minutes on the screen, the last part is not less than 6 minutes.

The division of the film into parts of 300 meters length is historically related to the fact that before the spread of modern powerful light sources providing long-term stable operation (for example, xenon lamps ), the professional arc projectors used a coal arc of intense burning - a source of light in which an electrical discharge occurs in the air between two carbon electrodes . In this case, the electrodes are burned, and in order to maintain a constant gap between them, they are moved by a special device, driven by a tape drive mechanism . The complete burning of the electrodes occurs within 15 minutes, after which their replacement is required. With the silent projection frequency of 16 frames per second, the length of the standard part was just 15 minutes. In addition, the majority of film standards were born in Hollywood , who actively participated in the development of new film technologies, and 300 meters are approximately equal to 1000 feet .

For 16 mm mobile cinema sets equipped with one film projector, film copies were often produced glued into rolls 600 m long. As a result, the full-length film could be shown in two parts with one break for reloading ^[1] . Short-length and educational 16-mm films were most often printed in parts 120 meters long.

Stationary film projection installations have at least two film projection devices (posts) ^[1] . This makes it possible to show films without interruption between parts.

However, the process of switching between posts, depending on the state of the projection technique and the accuracy of the work of the projectionist, may not occur strictly synchronously. Therefore, in order to avoid “falling out” of the material and “swallowing” a part of the sound, when mounting a film, the boundaries between parts of the film are combined with editing transitions , scene changes and do not allow plot-important moments to go from part to part. The length of each part, installed during installation, cannot exceed 300 meters for films of 35 mm rolling formats ^{[3] [4]} . With the compilation of film prints at the film-copying factory, parts are selected according to optical density and color reproduction, which minimizes the visibility of transitions between parts for the audience ^[5] .

Modern film screening technology involves the use of non - rewinding devices - printers - allowing to glue the film into one common roll and eliminate the transition between posts. However, transportation and storage of film copies is allowed only in separate parts ^[6] . Therefore, gluing into a common roll is made directly in the equipment of a particular movie theater , and after the picture is rolled out, the film is cut into its original parts with reverse pasting of remote leader tape .

The impossibility of continuous film demonstration for more than 10 minutes leaves an imprint on the technology of film production and features of the work of writers . The directorial script of any film is compiled with the expectation that the duration of a frame cannot exceed the specified length ^[7] . When editing a film, first the working positive and then the original negative are glued into rolls of the specified length ^[4] . The restrictions are aggravated by the design of most general-purpose film-making devices , the limiting capacity of the cassettes of which does not exceed 300 meters of 35 mm film.

In itself, such a restriction is not a problem, since the laws of installation require dynamism and force us to avoid long installation plans. Even lengthy acting dialogues , as a rule, are filmed in a multi-chamber way with numerous assembly gluing. Attempts to overcome technological limitations were made mainly by innovative directors. The most famous example is Alfred Hitchcock's film “The Rope ”, which was shot in such a way that the transitions between the parts are masked by the figures of the actors obscuring the screen during the passage in front of the camera ^[8] . As a result, an illusion of a film shot in one shot is created.

It was possible to completely eliminate the division of the picture into parts only with the advent of digital cinema , due to the absence of fundamental restrictions on the capacity of digital movie camera drives. The film “ Russian Ark ”, shot in 2001 without stopping the camera, was one of the first in the history of cinema, not subject to technical limitations ^[9] . The year before, the Time Code film was shot in the United States in the same way.

The practice of gluing several parts into large rolls to reduce the number of transitions between projection posts leads to a permanent loss of 1-2 frames when cutting a roll for transportation. Frequent glueing of parts during rental in different cinemas leads to the fact that entire scenes are lost, and for some films there are several different, slightly different, projection duration of formally identical variants. And if you lose the original film and restore it from a rolling copy, a version of the film appears that is noticeably different from the original one. Such, in particular, is the fate of the French painting “ Fanfan-Tulip ” . The reason for the loss of scenes was sometimes the excision of “successful” frames by projectionists who made slides from them ^[10] .

• Post projection
• Platter
• Installation

• E. A. Iofis . Photo kinotekhnika / I. Yu. Shebalin. - M .: “Soviet Encyclopedia”, 1981. - p. 420. - 447 p.

• E. A. Iofis . Chapter VI. Processing film after shooting // "Film and photo processes and materials . " - 2nd ed. - M .: "Art", 1980. - p. 147-174. - 239 s.

• E. A. Iofis . Chapter I. Films // Films and their processing / V. S. Bogatova. - M .: "Art", 1964. - p. 5-23. - 300 s.

• B. N. Konoplev . Basics of film production / V. S. Bogatova. - 2nd ed .. - M .: "Art", 1975. - 448 p. - 5000 copies

• Ya. Butovsky, I. Vigdorchik. Film editing technology / T.S. Zinovyeva, L.O. Eisymont. - M .: "Art", 1968. - 127 p.

• V.D. Gribov, N.N. Usachev. Unwinding devices / N. N. Kalinina. - SPb. : Editorial and Publishing Department SPbGUKiT , 2005. - 42 p.