A phase of photography that has a very broad scope is motion-picture work, the mechanics of which depend on this fact: If an object is looked at for a time and is suddenly removed from before the eye, the eye continues to see it for an appreciable time after its removal. This phenomenon is called “persistence of vision.” A motion-picture camera is so arranged that a long strip of film can be drawn past the lens in a series of jerks, the shutter being opened to permit the image projected by the lens to fall on the film during the period that the latter is at rest; the film is drawn on to the next position while the shutter is closed. Naturally, an object moving before the lens will move slightly during the interval between exposures, so the film, when developed, shows a consecutive series of photographs of the object in slightly different positions. A positive print is made from this series of negatives on a similar strip of film. This is projected by means of an apparatus something like the familiar magic lantern or stereopticon, but so arranged that this film may be drawn along in jerks. Each photograph is shown for a fraction of a second, and is replaced, during the time that the shutter is closed, by one showing a slightly later phase of the motion. Because of the persistence of vision the eye blends these successive photographs into one apparently continuous motion. It will be seen that the term “moving pictures” is really a misnomer, since the pictures on the screen do not move, but remain perfectly stationary during the time that they are seen. By taking the pictures rapidly and projecting them slowly the apparent motion may be slowed down, so that a rifle bullet may take three or four minutes to travel across a screen space of as many feet. By taking them at wide intervals and projecting rapidly the motion may be speeded up, and a plant may seem to grow from a seedling to maturity in a few minutes. The ordinary taking and projecting speed is sixteen pictures per second, experiment having shown that this is the least number that the eye will blend satisfactorily. Since each picture is one inch wide by three-quarters of an inch high—in the film—it is evident that each second of time represents one foot of film. The writer has seen a rather elaborately staged photo-play that required an hour and forty minutes for projection; a simple calculation shows that this involved 6,000 feet of positive film—a little over a mile. The length of the negative film was undoubtedly more, on account of retakes, cuts, and so on. An expenditure of five or six hundred dollars for film, however, is but a small item in the cost of producing an elaborate photo-play, for the actors receive large salaries—though not so large as the press-agents would have us believe—and the cost of scenery is great. The production of photo-plays is nevertheless a profitable industry, as may be understood from the fact that the average daily attendance in this country is estimated at about twelve million. Assuming that each spectator pays only ten cents, this represents an intake of $1,200,000 daily and, as is well known, the prices of admission in many theatres range from 25 cents up to $1.00 and more. The artistic possibilities of the motion-picture play are obviously limited—it can never hope to rise to the emotional heights of the legitimate drama—but they are none the less considerable. It is to be regretted that the motion picture industry is at present so much in the hands of producers who pander to the coarser instincts of the public, through sensationalism and slap-stick farce; who are often indifferent to detail—the writer has seen a cow-puncher represented as wearing his six-shooter butt-foremost; who treat the author’s work according to their own ideas. A well-known author remarked, on seeing the screen version of one of her books: “If I hadn’t been fairly familiar with the story I wouldn’t have known what it was all about.” In general, firms seem to be more concerned with getting the public’s money than with producing really artistic results. The writer once saw a photo-play version of a fairly well-known book, in which the producer had changed an elderly, gray-haired, quiet, experienced cattleman into a cheap imitation of a Bret Harte gambler of thirty years of age, the purpose of this metamorphosis being to transform a noble and self-sacrificing affection into a piece of gaudy sensationalism. Such tactics cannot fail to displease thinking people, but there are, fortunately, producers to whom these remarks do not apply—really conscientious men of high ideals, and signs are not wanting of an improvement in this regard. The motion picture, in worthy hands, can be made an educational medium of great value, not only in the dramatic art but in many other ways. Films frequently show scenes of historical interest, life in foreign lands, industries. Scientific subjects are treated, such as the peristaltic movements of the intestines and the action of the heart, photographed by means of the X-ray; also the life cycle of micro-organisms, the microscope being used in this case—and many other activities of life. Among the most interesting of these films are those produced by the Williamson brothers, showing sea life, though mechanical difficulties have so far prevented the photographing of the most interesting phase of marine life, that of the extreme depths.
WRITTEN FOR THE MENTOR BY PAUL L. ANDERSON
ILLUSTRATION FOR THE MENTOR. VOL. 6, No. 12, SERIAL No. 160
COPYRIGHT, 1918, BY THE MENTOR ASSOCIATION, INC.
THE MENTOR ·· AUGUST 1, 1918
DEPARTMENT OF FINE ARTS
THE STORY OF PHOTOGRAPHY
By PAUL L. ANDERSON
Artist Photographer, Author of “Pictorial Photography”
MENTOR GRAVURES
PHOTOGRAPH FROM A DAGUERREOTYPE