The blue book of the screen (1923)

A close-up. FROM "FADE-IN" TO 'FADE-OUTMECHANISM OF THE PHOTOPLAY Moving pictures, from a mechanical standpoint, are a marvel of science, though our interest in the play and the players lulls our curiosity as to the method by which the effect we see on the screen is produced. "Moving pictures," in reality, is a misnomer; the pictures do not move. The illusion of motion results from the fact that the human eye is incapable of detecting what really takes place on the screen because the eye is not quick enough. If an object at which we are looking be removed and replaced to exactly the same position sixteen times in a single second, the fact that it has been removed will not be detected by the eye at all. We will think it has been there all the time! Scientific gentlemen, with their customary fondness for long names, call this the phenomenon of "persistence of vision"; it is fortunate, indeed, that we are all afflicted with this peculiarity, for without it motion pictures would be impossible. The pictures reach the theater in the form of a long and narrow strip of film, of a standard size. The camera by which the pictures are taken is so constructed that by turning a crank, snapshots are taken at the rate of sixteen a second. When the camera is directed at moving objects, therefore, a series of pictures is impressed upon the film, each of which differs from the preceding one by just the amount of motion that has taken place among the objects in the brief interval between the exposures. >^W< A film company's trademark. The projection room of one of San Francisco's largest theaters. Courtesy Granada Theater, San Francisco. 338