Popular Science Monthly/Volume 52/December 1897/Animated Pictures
By J. MILLER BARR.
A NEW and wonderful field in the realm of photography has lately been opened up to the world—a field whose extent, variety, and richness are as yet scarcely realized, though its assiduous cultivation by inventive minds has already afforded a harvest of interesting results.
The nature of this new domain is pointed out by the title of our present sketch. Aided by ingenious devices, the scientific photographers of to-day are enabled to portray motion in all its varied forms with a realism that impresses the beholder. They have, in effect, contrived to breathe life into normally changeless records of the camera; and the process is now applied, with marked success, to animated scenes of the most diverse description. The busy traffic of city streets, the play of expression upon the human countenance, the movements of waves, waterfalls, fleeting clouds—these and many other effects have been depicted upon the screen with equal fidelity before audiences that have seldom failed to show their appreciation of the novel form of entertainment thus provided.
It is true that these "motion views" are subject to certain imperfections. Apart from the flashing or pulsating effect which distinguishes the pictures, there are frequent blemishes, arising in part from mechanical, in part from photographic and other causes.
|Section of Film (actual size).|
A squad of soldiers at drill.
Chief among these causes must be mentioned the use of faulty apparatus and of films of inferior quality, or which have become worn by frequent and prolonged use. Minor blemishes are, however, of common occurrence, even when the best obtainable apparatus and materials are used for the purpose. These are referable chiefly to defects in the sensitized films of celluloid. But there is no reason to doubt that better films can be produced, and that pictures of this nature will ultimately be rendered as free from defects as are ordinary stereopticon views.
Meanwhile, these striking productions of the photographic art will doubtless continue to attract the world's attention. They have already become a source of much instructive entertainment to the public; and their usefulness, from this point of view, must be recognized by all. But the invention has other and more serious claims upon our consideration. As a means of permanently recording and vividly illustrating notable events its importance will scarcely be overestimated. The ordinary photography can depict for us only isolated phases in the varied phenomena of life or Nature; though the value of its precise records, from the historian's standpoint, has of course received ample recognition. But the charm of animation may henceforth be added to our portrayals of historic scenes. And, in like manner, we shall be enabled to record the mutable expressions, the gestures and mannerisms, as well as the features, of distinguished men and women; while the value of all such records must increase with the lapse of time. These aspects of our subject are, indeed, so attractive that one is tempted to dilate upon them at some length; but I shall content myself with a brief allusion to one recent event in which the whole world has evinced keen interest—viz., the celebration of the Diamond Jubilee of Her Majesty Queen Victoria. The Royal procession and other imposing features of the jubilee ceremonials were duly recorded upon cinematographic films, of which fine specimens were set aside for future preservation in England's National Museum. These have been "hermetically sealed and deposited in the museum, together with a machine and lantern, by means of which they may be exhibited to future generations."
We can only strive to realize, in some dim measure, the fascination which those pictured ribbons of celluloid will exercise upon the eyes and minds of future Londoners—let us say, at some remote epoch, when the throne of Great Britain will be occupied by a monarch of whom we can form no conception, under social conditions which may differ widely from those existing at the present day.
I have thus far alluded only to the more obvious uses of this beautiful invention. But the subject, as we shall presently see, may be regarded from two very distinct points of view. On the one hand, we are concerned with the ordinary animated pictures, whose properties and functions are already known to the public; on the other, we have to deal with movements originally imperceptible to the eye, but which can be rendered visible upon a screen if the slow-moving bodies are photographed under conditions described in a subsequent part of this article. Pictures of this kind may, for convenience, be spoken of as motion views of the second type. Such pictures have not, I think, been produced up to the present time. But this aspect of the subject, though hitherto neglected (if not wholly overlooked), is deeply interesting and merits the most careful investigation. It will, accordingly, engage our especial notice, though the reader will first be led to consider in a general way the methods and principles upon which depend the production of ordinary animated photographs.
Although the kinetoscope and cinematograph are regarded as distinctively modern contrivances, it should be borne in mind that they represent only the recent development of a principle that has long been familiar to students of optical science. They are the descendants, so to speak, of more primitive forms of apparatus, among which may be specially mentioned the zoetrope and the phenakistiscope. The latter instrument—an optical toy devised by the famous French physicist Plateau—merits particular notice, since it apparently represents the first stage in that process of evolution which has led up to the elaborate motion-picture machines of the present day.
Though differing much in the details of their construction, these various machines are designed to fulfill the same general purpose— viz., the display in rapid sequence of a long series of photographs, which hence convey to the eye and brain the impression of a continuous and animated scene. In the kinetoscope the small pictures are viewed through an enlarging lens by reflected light, whereas in the cinematograph, phantascope, vitascope, etc., they are projected upon a screen—a plan that is obviously best suited to the requirements of a public exhibition.
A machine of the last-mentioned type may be shortly described as a stereopticon, combined with such mechanism as is requisite for the precise manipulation of the celluloid picture film. When the
Machine for Projecting Animated Pictures on the Screen. The phantascope, latest model, being an attachment for a J. B. Colt & Co. electric lantern.
apparatus is set in motion the long band of celluloid passes quickly, though not continuously, behind the projecting lens, between spools or bobbins which revolve at a uniform rate. While thus passing from its original spool to the winding reel the film encounters certain pulleys and toothed rollers that serve to accurately direct its movements. Along its edges are numerous small perforations, into which the teeth of the rollers fit with precision; and by this means the small transparencies are made to occupy exactly similar positions when their images are projected upon the canvas. As each picture in its turn attains this critical position, it is momentarily brought to a standstill. At the same time a shutter is opened and an image of the picture flashes for an instant upon the screen. The shutter is then quickly closed, the picture resuming its motion, while its successor in the series is brought into a similar fixed situation.
This temporary stoppage of the film (or rather of a portion thereof), as each picture attains its proper place behind the projecting lens, is a very essential feature of the process. It is effected by various ingenious devices, among which those of Acres, Edison, and the Lumière brothers are deserving of special notice. Without, however, attempting to describe these diverse forms of apparatus, I will try to indicate in general terms the means by which an intermittent motion of the film is secured. Let us assume that a picture has arrived at the fixed position already referred to. At the instant of its arrival, a portion of the film on the preceding side of the picture will be in an unstrained or slack condition. The "slack" is then taken up by a continuously moving sprocket pulley, whereupon a rod or roller is quickly brought to bear against the now tightened film, pressing it to one side and as quickly releasing it. By this movement the next picture is pulled into its fixed position, while the film is made taut (or nearly so) on the following side of this picture. These operations are repeated continuously until the entire film has passed through the holding device in rear of the lens. The process may be compared, in a general way, with the automatic feeding of a web of paper to an ordinary printing press.
A specially constructed camera is used in taking the negatives from which ultimately motion pictures are obtained. This camera is provided with mechanism generally similar to that employed in showing the photographs. Indeed, the selfsame mechanism has frequently been used for both purposes. The picture roll is replaced by a reel of sensitized film, upon which the exposures are made in quick succession when the apparatus is set in motion. From twenty-five to fifty photographs are thus "laid on" in a second of time. The films range in length from fifty to two hundred feet, and contain when finished from eight hundred to more than three thousand tiny negatives.
After exposure the film is subjected to the usual photographic operations. These are, however, conducted with special arrangements, rendered necessary by the inordinate length of the film. The latter is subsequently made to pass, in contact with a second sensitized film, beneath an incandescent lamp, whereby the photographs are impressed or "printed" upon the sensitive surface. This second film in its turn is passed through the various photographic processes. When complete, it is wound upon a spool, and is then ready to be placed in the cinematograph or other machine used in exhibiting the pictures. Here, as already stated, the mechanical arrangements correspond to those employed in taking the negatives.
The Jenkins Camera, with rotating system of lenses; capable, in sunlight, of taking one hundred pictures per second.
Thus the pictures, when displayed before an audience, are seen to flash out in the same rapid sequence in which the original scenes were presented to the "eye of the camera."
A homely illustration may aid the reader in arriving at a perfectly clear comprehension of this subject. Let us take the case of a man who is slowly walking past a high picket fence and gazing intently at some moving object on the other side of the fence. His view will be interrupted at regular intervals by the pickets as they successively encounter his line of sight. But if he proceed more quickly a seemingly continuous view of the object in question will be obtained, though rapid alternations in its brightness will be manifested. These effects are due to a well-known cause—viz., the persistence of luminous impressions upon the human retina. Thus, our observer's eye retains for a brief period its impression of each momentary glimpse that is afforded him under the conditions just described; and the successive visual images become merged into one another, while the rapid fading of these retinal impressions gives rise to the pulsating effect that is familiar to everybody.
Now, the well-known optical phenomena which I have here attempted to describe are, in fact, closely analogous to those exhibited by the animated pictures. In the former case we have to deal with a moving body; in the latter, with photographs of such bodies; and since the momentary images in the first-mentioned case are practically changeless, it is evident that a similar general effect must be produced upon the organ of vision.
We have hitherto been concerned with motion pictures of the ordinary type—those, namely, which reproduce with accuracy the movements of the original scenes. In order to secure this result it is essential that our pictures be "taken" and exhibited at the same rate per unit of time. Where this condition has not been fulfilled, it is manifest that the pictured objects must appear to move either quicker or more slowly than their originals. If the difference in rate be small, its results will hardly be noticeable; if large, a curious but awkward and unnatural effect will be produced.
Suppose now the mechanism of our camera to be altered in such wise that successive exposures may be made at relatively long intervals of time, while the duration of each exposure can be varied at will. With this end in view, the camera should be provided with clockwork capable of running for twenty-four hours continuously. Thus equipped, we should be ready to experiment on objects—such as growing plants—whose changes are of too gradual a nature to be perceived by the eye.
An ordinary house plant—let us say a geranium, abutilon, or hyacinth—would form an admirable subject for the purpose. The photographs might be taken under the electric light at intervals of an hour or more, though plants of rapid growth (such as climbers) might well be photographed at much shorter intervals. As a uniform illumination is essential, it would be necessary to exclude daylight while taking the negatives. At night the light source could be maintained continuously—a condition which tends, as is well known, to stimulate the growth of plants. The experiments might extend over a period of weeks, or even of many months, according to the nature of the plant selected. But the resulting film, when placed in the cinematograph for exhibition, would be "reeled off" in the course of a minute or two, so that we should have, as it were, a greatly magnified representation of the movements involved in plant growth. If, for example, our pictures were taken at half-hourly intervals, and shown at a speed of fifty per second, the apparent rate of growth of the plant would be increased no less than ninety thousand times. A slower rate would evidently correspond to a diminished time interval between successive negatives; and this interval should in all cases be so chosen as to insure gradual (though distinctly perceptible) changes in the resulting pictures.
Such views could not fail to produce an effect at once marvelous, unique, and instructive. As pictured upon the canvas, the plants would grow and develop before the eyes of onlookers, throwing out leaf upon leaf, and visibly increasing their dimensions. Here and there a flower or flower cluster might make its appearance, the individual blossoms bursting forth suddenly and remaining visible for a brief period only. The process is clearly applicable to greenhouse or indoor plants of every description, from stately palms or tree ferns down to the most delicate mosses or lichens. Thus, the general phenomena of plant growth may be illustrated with a vividness never before realized. As object lessons in botany, such motion pictures would be invaluable, while the general public, not less than the advanced student of science, would regard them with feelings of the keenest interest.
Instead of photographing an entire plant, we might direct our efforts to the representation of its more interesting details. Thus, an expanding leaf bud or a flower stalk would furnish highly attractive views for the cinematograph. The microscope, too, could be brought to bear, and with its aid we should be enabled to depict the more delicate and subtle processes of vegetable growth. Such optical studies would be not merely instructive in the ordinary sense of that term, but they would be likely to throw new light on biological problems of the deepest interest. For we are here concerned with changes which can not be directly observed, and whose nature can only be imperfectly apprehended from a comparison of ordinary photographs taken for the purpose. We know, for example, that common instantaneous views of men or animals in motion convey a most imperfect idea of the actual movements involved in walking or running; and a similar remark would doubtless apply with greater force in cases where the pictured objects were undergoing changes of a complex physical nature; so that the human eye, aided by the sensation of motion, might well succeed in bringing to light laws or relations hitherto unrecognized by botanists.
|An Approaching Train.|
Compare upper and lower views of the film.
This graphic method should theoretically be applicable to insects and animals as well. as to plants. In practice, however, it can be successfully applied only to the lower and the higher forms of animal life. On the one hand, we could picture the growth of certain lowly organisms in the border land between the animal and vegetable worlds; on the other, we could portray the development of a child, or even the life changes of a human being from childhood to old age. Pictures of the latter class may evidently be taken at daily intervals; uniformity in position and expression, as well as in the clothing or drapery of the subject, being essential requisites to success in all such cases.
In dealing with subjects of this nature we must take into account the inevitable deterioration of the sensitive films through lapse of time. It will become necessary, in fact, to use shorter films whenever the negative series is much prolonged. Such films could be treated separately, and afterward joined together so as to form one long strip—a procedure involving only the exercise of a little care and the use of some celluloid solution. From this composite negative film a single uniform roll of pictures would ultimately be obtained by the usual process.
The application of this method to outdoor objects will in general be greatly restricted, owing in part to the variable light and partly also to the influence of wind and weather. Some picturesque effects could, however, be obtained by photographing natural scenery under varying angles of solar illumination—especially in mountainous regions and near the time of sunrise or sunset, when the most striking changes would be manifested. Seasonal variations, too, might be illustrated by depicting scenery in a forest from day to day for months in succession. Owing to the gradual nature of such changes it would be practicable to take several negatives at about the same hour of each day, an actinometer being used, and the exposures varied in accordance with its indications. The operations might thus be omitted during bad weather, an additional number of photographs being taken on succeeding fine days. Some very pleasing views for the cinematograph could without doubt be obtained by this mode of procedure.
Turning now from the earth to the heavens, we shall see that similar methods are applicable to the most prominent of celestial bodies—viz., the sun. The photographic art has long since been applied with conspicuous success to the glowing solar disk, with its dark spots and brighter patches or "faculæ"; and such photographs are now taken from day to day at leading observatories in various parts of the globe. During recent years, moreover, astronomers have contrived to photograph, under ordinary conditions, the surroundings of the great luminary—including the chromosphere and prominences, but excepting the corona, which can not as yet be studied in the absence of an eclipse.
I shall not attempt to describe the many interesting features shown in such photographs; nor is it necessary in this place to indicate the precise means whereby solar picture films can be produced. The chief point to be noted is that changes—often of a rapid and striking character—are continually occurring both in the sun's photosphere and its gaseous surroundings. The cinematograph will enable us to actually see such changes taking place; and it may be possible in this way to obtain new light on certain fascinating, though recondite, problems presented by the sun, while the complex solar movements may in any case be pictured in a manner that can not fail to prove deeply interesting and instructive.
Although the common motion views are often described as realistic, there are two respects in which they fail to correctly represent the original scenes. Not only do they lack the charm of color (which adds so much to the variety and interest of ordinary scenes), but the effect of solidity, due to our binocular vision, is also absent. As regards the reproduction of color, we shall have to rest content—at least for some time to come—with monochromic views of ordinary moving objects. Instantaneous photography in colors is not yet possible, nor is it likely to be achieved in the near future. In the color process of M. Lippmann, for example, it is necessary to expose the sensitive plates for relatively long periods of time. It may be questioned, also, whether such photographs could be successfully produced upon celluloid films. And even if these objections were moved, there would remain another serious drawback—viz., that such pictures must be viewed by reflected light, and hence can not be projected upon a screen in the usual way.
But there are other methods of obtaining colored pictures which merit careful consideration from our present point of view. One of these methods is so clearly applicable in the production of motion views of the second type that I need offer no apology for the brief account of it given below:
A camera fitted with special apparatus—including three carefully selected color screens—is used in taking the negatives. The arrangements are such that three separate images—red, blue, and green-yellow—of the scene or subject are thrown upon the sensitive (isochromatic) plate. The result is a triple negative, from which a transparency is obtained by the usual procedure. If now this transparency be placed in a lantern provided with a triple objective and with color screens similar to those used in taking the pictures, the three colored images of the transparency may be brought into coincidence upon the screen. And since the tints of the glasses correspond to the three primary color sensations, a picture in natural hues will be thus produced. The process, in its perfected form, is due to Mr. Frederic E. Ives, of Philadelphia, who has in this way been able to reproduce the colors of flowers and of natural scenery with complete success.
Now, there is no reason to doubt that similar results can be secured by using films instead of glass plates; so that Mr. Ives's ingenious system (or some modification thereof) may probably be adapted for use with mechanism similar to that of the cinematograph.
We may thus hope to obtain striking and beautiful representations of plant life, in which not only the forms and movements of leaves, stalks, or flowers, but also their glowing colors, will appear upon the canvas.
The realism of our motion pictures may also be enhanced by imparting to them the quality of relief, as in the stereoscope. We may utilize for this purpose a clever invention known as the lantern stereoscope, whereby stereo views can be shown upon a screen, the pictures being viewed through instruments resembling opera glasses in external appearance. It will be possible in this way to exhibit animated views of every description in distinct stereoscopic relief. Each member of the audience must, of course, be provided with one of the binocular instruments above referred to; and it is almost needless to add that the projecting machine, as also the camera used in taking the stereo negatives, must be of duplicate construction.
The phonograph—or graphophone—has frequently been used in combination with machines for the production of motion views. By such means Edison hoped to reproduce the sounds accompanying many scenes with such perfection that it would be possible to represent, for example, the complete performance of an opera or a drama, with all its accessories. Up to the present time, however, these anticipations have not been realized. The rich song notes of a Patti or a Melba can not yet be satisfactorily stored up in the phonographic cylinder, to be given out when required with the full tone and perfect expression of the artist. But better things may be looked for in the near future, and it is probable that Edison's attractive scheme will, sooner or later, be carried into effect.
In an ideal exhibition of this nature we should see the animated views appear upon the screen in relief and in their natural tints, while the sounds appropriate to certain scenes would be reproduced with as much fidelity as the optical impressions. Much remains to be done before this ideal can be fully realized; but in the meantime it will be possible, with our present resources, to make some progress in this direction, and to obtain pictures of a novel and instructive type, by proceeding along the lines which I have attempted to define in the present article.
- This effect can be got rid of only by considerably increasing the rate per second at which the individual pictures are shown. When, however, this rate is as high as forty or fifty per second of time, the light-pulsations are hardly noticeable, and can not be said to mar the pictures in any appreciable degree.
- See accompanying illustration of the phantascope. For this picture, and for the other photographs here reproduced, I am indebted to Mr. C. Francis Jenkins, of Washington, D. C., inventor of the phantascope, and the author of various notable improvements connected with this branch of photography.
- These small square holes—usually six or eight for each picture—are punched out with great precision by a machine made for the purpose. They insure correct register, not only in exhibiting but also in "printing" the photographs.
- In some forms of apparatus, such as the vitascope and phantascope, the shutter is omitted. The intermittent motion of the film does not seem to mar the continuity of the pictures, which are also more fully illuminated in the absence of a shutter.
- The Jenkins camera (see illustration) forms an interesting exception to this general rule.
- The analogy will be rendered more exact if we assume that one eye only is used by our observer in viewing the moving object. Binocular vision would modify, to a perceptible extent, the appearances presented.
- An incandescent lamp would probably give the best results, though gas or oil flames could evidently be utilized.
- Although the motion views do not commonly endure beyond these limits, it should be noted that a much longer duration—involving the use of many films—is now practicable.
- We are here concerned with movements which, though invisible to the observer's eye, take place in reality with very great rapidity.
- It is too soon, as yet, to express any definite opinion with respect to the new Dansac process and some other heliochromic methods of recent origin.
- The principle of the polarization of light is effectively utilized in this very ingenious contrivance.