Edison: His Life and Inventions

by Frank Lewis Dyer; Thomas Commerford Martin

One of the earliest suggestions of the possibility of utilizing photography for exhibiting the illusion of actual movement was made by Ducos, who, as early as 1864, obtained a patent in France, in which he said: "My invention consists in substituting rapidly and without confusion to the eye not only of an individual, but when so desired of a whole assemblage, the enlarged images of a great number of pictures when taken instantaneously and successively at very short intervals.... The observer will believe that he sees only one image, which changes gradually by reason of the successive changes of form and position of the objects which occur from one picture to the other. Even supposing that there be a slight interval of time during which the same object was not shown, the persistence of the luminous impression upon the eye will fill this gap. There will be as it were a living representation of nature and . . . the same scene will be reproduced upon the screen with the same degree of animation.... By means of my apparatus I am enabled especially to reproduce the passing of a procession, a review of military manoeuvres, the movements of a battle, a public fete, a theatrical scene, the evolution or the dances of one or of several persons, the changing expression of countenance, or, if one desires, the grimaces of a human face; a marine view, the motion of waves, the passage of clouds in a stormy sky, particularly in a mountainous country, the eruption of a volcano," etc.

Other dreamers, contemporaries of Ducos, made similar suggestions; they recognized the scientific possibility of the problem, but they were irretrievably handicapped by the shortcomings of photography. Even when substantially instantaneous photographs were evolved at a somewhat later date they were limited to the use of wet plates, which have to be prepared by the photographer and used immediately, and were therefore quite out of the question for any practical commercial scheme. Besides this, the use of plates would have been impracticable, because the limitations of their weight and size would have prevented the taking of a large number of pictures at a high rate of speed, even if the sensitized surface had been sufficiently rapid.

Nothing ever came of Ducos' suggestions and those of the early dreamers in this essentially practical and commercial art, and their ideas have made no greater impress upon the final result than Jules Verne's Nautilus of our boyhood days has developed the modern submarine. From time to time further suggestions were made, some in patents, and others in photographic and scientific publications, all dealing with the fascinating thought of preserving and representing actual scenes and events. The first serious attempt to secure an illusion of motion by photography was made in 1878 by Edward Muybridge as a result of a wager with the late Senator Leland Stanford, the California pioneer and horse-lover, who had asserted, contrary to the usual belief, that a trotting-horse at one point in its gait left the ground entirely. At this time wet plates of very great rapidity were known, and by arranging a series of cameras along the line of a track and causing the horse in trotting past them, by striking wires or strings attached to the shutters, to actuate the cameras at the right instant, a series of very clear instantaneous photographs was obtained. From these negatives, when developed, positive prints were made, which were later mounted on a modified form of Zoetrope and projected upon a screen.

One of these early exhibitions is described in the Scientific American of June 5, 1880: "While the separate photographs had shown the successive positions of a trotting or running horse in making a single stride, the Zoogyroscope threw upon the screen apparently the living animal. Nothing was wanting but the clatter of hoofs upon the turf, and an occasional breath of steam from the nostrils, to make the spectator believe that he had before him genuine flesh-and-blood steeds. In the views of hurdle-leaping, the simulation was still more admirable, even to the motion of the tail as the animal gathered for the jump, the raising of his head, all were there. Views of an ox trotting, a wild bull on the charge, greyhounds and deer running and birds flying in mid-air were shown, also athletes in various positions." It must not be assumed from this statement that even as late as the work of Muybridge anything like a true illusion of movement had been obtained, because such was not the case. Muybridge secured only one cycle of movement, because a separate camera had to be used for each photograph and consequently each cycle was reproduced over and over again. To have made photographs of a trotting-horse for one minute at the moderate rate of twelve per second would have required, under the Muybridge scheme, seven hundred and twenty separate cameras, whereas with the modern art only a single camera is used. A further defect with the Muybridge pictures was that since each photograph was secured when the moving object was in the centre of the plate, the reproduction showed the object always centrally on the screen with its arms or legs in violent movement, but not making any progress, and with the scenery rushing wildly across the field of view!

In the early 80's the dry plate was first introduced into general use, and from that time onward its rapidity and quality were gradually improved; so much so that after 1882 Prof. E. J. Marey, of the French Academy, who in 1874 had published a well-known treatise on "Animal Movement," was able by the use of dry plates to carry forward the experiments of Muybridge on a greatly refined scale. Marey was, however, handicapped by reason of the fact that glass plates were still used, although he was able with a single camera to obtain twelve photographs on successive plates in the space of one second. Marey, like Muybridge, photographed only one cycle of the movements of a single object, which was subsequently reproduced over and over again, and the camera was in the form of a gun, which could follow the object so that the successive pictures would be always located in the centre of the plates.

The review above given, as briefly as possible, comprises substantially the sum of the world's knowledge at the time the problem of recording and reproducing animate movement was first undertaken by Edison. The most that could be said of the condition of the art when Edison entered the field was that it had been recognized that if a series of instantaneous photographs of a moving object could be secured at an enormously high rate many times per second—they might be passed before the eye either directly or by projection upon a screen, and thereby result in a reproduction of the movements. Two very serious difficulties lay in the way of actual accomplishment, however—first, the production of a sensitive surface in such form and weight as to be capable of being successively brought into position and exposed, at the necessarily high rate; and, second, the production of a camera capable of so taking the pictures. There were numerous other workers in the field, but they added nothing to what had already been proposed. Edison himself knew nothing of Ducos, or that the suggestions had advanced beyond the single centrally located photographs of Muybridge and Marey. As a matter of public policy, the law presumes that an inventor must be familiar with all that has gone before in the field within which he is working, and if a suggestion is limited to a patent granted in New South Wales, or is described in a single publication in Brazil, an inventor in America, engaged in the same field of thought, is by legal fiction presumed to have knowledge not only of the existence of that patent or publication, but of its contents. We say this not in the way of an apology for the extent of Edison's contribution to the motion-picture art, because there can be no question that he was as much the creator of that art as he was of the phonographic art; but to show that in a practical sense the suggestion of the art itself was original with him. He himself says: "In the year 1887 the idea occurred to me that it was possible to devise an instrument which should do for the eye what the phonograph does for the ear, and that by a combination of the two, all motion and sound could be recorded and reproduced simultaneously. This idea, the germ of which came from the little toy called the Zoetrope and the work of Muybridge, Marey, and others, has now been accomplished, so that every change of facial expression can be recorded and reproduced life-size. The kinetoscope is only a small model illustrating the present stage of the progress, but with each succeeding month new possibilities are brought into view. I believe that in coming years, by my own work and that of Dickson, Muybridge, Marey, and others who will doubtless enter the field, grand opera can be given at the Metropolitan Opera House at New York without any material change from the original, and with artists and musicians long since dead."

In the earliest experiments attempts were made to secure the photographs, reduced microscopically, arranged spirally on a cylinder about the size of a phonograph record, and coated with a highly sensitized surface, the cylinder being given an intermittent movement, so as to be at rest during each exposure. Reproductions were obtained in the same way, positive prints being observed through a magnifying glass. Various forms of apparatus following this general type were made, but they were all open to the serious objection that the very rapid emulsions employed were relatively coarse-grained and prevented the securing of sharp pictures of microscopic size. On the other hand, the enlarging of the apparatus to permit larger pictures to be obtained would present too much weight to be stopped and started with the requisite rapidity. In these early experiments, however, it was recognized that, to secure proper results, a single camera should be used, so that the objects might move across its field just as they move across the field of the human eye; and the important fact was also observed that the rate at which persistence of vision took place represented the minimum speed at which the pictures should be obtained. If, for instance, five pictures per second were taken (half of the time being occupied in exposure and the other half in moving the exposed portion of the film out of the field of the lens and bringing a new portion into its place), and the same ratio is observed in exhibiting the pictures, the interval of time between successive pictures would be one-tenth of a second; and for a normal eye such an exhibition would present a substantially continuous photograph. If the angular movement of the object across the field is very slow, as, for instance, a distant vessel, the successive positions of the object are so nearly coincident that when reproduced before the eye an impression of smooth, continuous movement is secured. If, however, the object is moving rapidly across the field of view, one picture will be separated from its successor to a marked extent, and the resulting impression will be jerky and unnatural. Recognizing this fact, Edison always sought for a very high speed, so as to give smooth and natural reproductions, and even with his experimental apparatus obtained upward of forty-eight pictures per second, whereas, in practice, at the present time, the accepted rate varies between twenty and thirty per second. In the efforts of the present day to economize space by using a minimum length of film, pictures are frequently taken at too slow a rate, and the reproductions are therefore often objectionable, by reason of more or less jerkiness.

During the experimental period and up to the early part of 1889, the kodak film was being slowly developed by the Eastman Kodak Company. Edison perceived in this product the solution of the problem on which he had been working, because the film presented a very light body of tough material on which relatively large photographs could be taken at rapid intervals. The surface, however, was not at first sufficiently sensitive to admit of sharply defined pictures being secured at the necessarily high rates. It seemed apparent, therefore, that in order to obtain the desired speed there would have to be sacrificed that fineness of emulsion necessary for the securing of sharp pictures. But as was subsequently seen, this sacrifice was in time rendered unnecessary. Much credit is due the Eastman experts—stimulated and encouraged by Edison, but independently of him—for the production at last of a highly sensitized, fine-grained emulsion presenting the highly sensitized surface that Edison sought.

Having at last obtained apparently the proper material upon which to secure the photographs, the problem then remained to devise an apparatus by means of which from twenty to forty pictures per second could be taken; the film being stationary during the exposure and, upon the closing of the shutter, being moved to present a fresh surface. In connection with this problem it is interesting to note that this question of high speed was apparently regarded by all Edison's predecessors as the crucial point. Ducos, for example, expended a great deal of useless ingenuity in devising a camera by means of which a tape-line film could receive the photographs while being in continuous movement, necessitating the use of a series of moving lenses. Another experimenter, Dumont, made use of a single large plate and a great number of lenses which were successively exposed. Muybridge, as we have seen, used a series of cameras, one for each plate. Marey was limited to a very few photographs, because the entire surface had to be stopped and started in connection with each exposure.

After the accomplishment of the fact, it would seem to be the obvious thing to use a single lens and move the sensitized film with respect to it, intermittently bringing the surface to rest, then exposing it, then cutting off the light and moving the surface to a fresh position; but who, other than Edison, would assume that such a device could be made to repeat these movements over and over again at the rate of twenty to forty per second? Users of kodaks and other forms of film cameras will appreciate perhaps better than others the difficulties of the problem, because in their work, after an exposure, they have to advance the film forward painfully to the extent of the next picture before another exposure can take place, these operations permitting of speeds of but a few pictures per minute at best. Edison's solution of the problem involved the production of a kodak in which from twenty to forty pictures should be taken IN EACH SECOND, and with such fineness of adjustment that each should exactly coincide with its predecessors even when subjected to the test of enlargement by projection. This, however, was finally accomplished, and in the summer of 1889 the first modern motion-picture camera was made. More than this, the mechanism for operating the film was so constructed that the movement of the film took place in one-tenth of the time required for the exposure, giving the film an opportunity to come to rest prior to the opening of the shutter. From that day to this the Edison camera has been the accepted standard for securing pictures of objects in motion, and such changes as have been made in it have been purely in the nature of detail mechanical refinements.