MOVING PICTURES, also known as cinema and biograph pictures, an inven tion whereby a rapid succession of photo graphs, thrown on a screen, each suc ceeding picture presenting a slight degree of progress in physical action over the preceding one, produces the optical delu sion of actual movement. So highly de veloped has this process become that dramatic stories, or narratives, may be told solely through action, with the re sult that moving pictures have become the most popular means of this class of amusement in practically all countries.
The invention is the result of numerous experiments made by photographers, sug gested to them by the old-fashioned zoe trope, which was popular before and after 18G0, whereby pictures of figures in various stages of action, printed on strips of paper, whirled about in a ma chine, which enabled observation through opulent of the invention, but in its util ization in the field of amusements and pictorial education.
As now operated, the actual pictures are photographic positives printed on films, made of a substance resembling celluloid. The film is one and three sixteenths of an inch in width, and may be a thousand feet in length. These strip:, are passed before a powerful light within a machine, on the same principle as the old magic lantern, which projects slits, gave the delusion of action. The first experiments with photographs that gave practical results were made by an Amencan,Muybridge, in 1877, who photo graphed horses in action by means of the newly developed instantaneous process. The invention of the ribbon films, in 1880, constituted another step in advance toward the present state of perfection. The first utilization of the invention for amusement was made by Thomas Edison, in 1894, in the kinetoscope, whereby posi tives on a film, about the size of postage stamps, were passed before a light and gave the illusion of sustained action. The first moving pictures projected to a large size on screens, on the principle of the magic lantern, were perfected by Lurniere, in France, shortly after the appearance of Edison's kinetoscope. Since then there has been continuous improve ment, not only in the mechanical devel them on a white screen, where they are enlarged to much over life size, if neces sary. The film passes before the light
at a rate of speed averaging from 60 to 80 feet a minute, depending on the rapid ity of action desired for the figures on the screen.
Were this film to pass before the light continuously, the effect on the screen, as was observed in the early experiments, would be an indistinguishable blur. To produce the desired results, it is neces sary that each picture be retained on the screen, and there held stationary, for the slightest fraction of a second. During the interval between the presentation of one picture and the succeeding one, the screen must be dark. But so slight is this interval that it is not obvious to human perception, as now operated, though formerly the action was slow enough to produce the effect of observing a landscape from a train window passing rapidly along a picket fence.
It was the necessity of perfecting a mechanism to accomplish the above re sults that delayed the present perfection of the moving-picture machine. This has finally been accomplished by means of a wheel, resembling the paddle wheel of a stern-wheel river boat, which catches the films along the edges by means of ratchets, or spikes, catching in holes along the margins of the film. The wheel, revolving by rapid jerks, causes each picture to pause just the desired interval. Sixteen separate pictures are presented during the space of one second.
The moving-picture camera is con structed on a similar principle, the sensi tized film on which the negatives are made being exposed during the fraction of a second required for an instantane ous photograph. The rapidity with which this is done may be regulated by the photographer, who, by turning a crank, governs the action of the cam era. Where slow movement is desired, the mechanism is slowly turned, with the result that fewer pictures are taken to represent a given motion. Where quick action is involved, such as the galloping of a horse or the leaping of a human figure in a dramatic scene, the camera is turned correspondingly faster, so that a greater number of impressions may be registered on the film.