STRANGE DEVELOPMENTS IN PHOTOGRAPHY By EMMETT CAMPBELL HALL, ARTHUR WELTON, J. B. VAN BRUSSEL, Success of Telephotography By EMMETT CAMPBELL HALL OTO ANY persons are inclined to regard telephotography as one of the greatest recent achievements of modern science, combining as it does the two great inventions, photography and the telegraph. It has been, comparatively, but a few years since a photograph meant many minutes of plate exposure, and hours of long and careful work in the developing roomthe flashing of a message from the other side of the earth was undreamed of. Yet, at the present day, an event may. occur in London or Berlin, and within an hour photographic reproductions of the scene might be found in the news COPYRIGHT BY UNDERWOOD & UNDERWOOD, NEW YORK THE POST TRANSMITTER. papers selling upon the streets of New York or Chicago. The taking, developing and printing of a photograph is now a question of minutes, as is the process of half-tone reproduction, and the telephotography system can bridge the intervening ocean. Much attention was given in Germany recently to Professor Korn's invention for the transmission by wire of photographic reproductions. His latest experiments show that nearly as satisfactory results are secured by making use of ordinary telephone wires as on lines specially constructed for the purpose. The only difficulty encountered when using the telephone line was caused by calls on adjoining wires. The calls produced zig-zag lines on the reproduced The telegraphic portrait can be seen on the first cylinder. picture at the receiving station, but these lines may be easily corrected by retouching. Alterations in current intensity by ringing on or ringing off, as well as during conversation over adjoining wires, are without effect. Perhaps the most remarkable feature about the system, however, is that the wire used for the photographic reproduction can be simultaneously used for telephonic conversation, neither use interfering in the least with the other. The value of a successful telephotographic system is most obvious, its advantages to the press being especially great. It could also be used to great advantage in the cause of justice, as a photograph of a criminal who had eluded the officers of the law could be placed in the hands of the authorities of every city in the country within a few minutes, thus making his identification and capture almost certain. By means of the system a newspaper correspondent in a distant city could telegraph or telephone his dispatches, and at the same time transmit photographs to illustrate the text. That telephotography is a practical working system-though as yet not so complete in its operations as it will eventually become-and not a mere experiment, is evidenced by the fact that the Copenhagen daily Politiken, a large and progressive journal, has ordered a complete installation for telephonic and telephotographic communication with its Berlin office. It is expected that the new improvements in the instruments that have made the ready transmission of pictures possible will be applied commercially and widely in the near future. The general W M el THE BERLIN APPARATUS SEEN IN FRONT. plan of the instruments has been previously described and the earlier machines have been pictured. The new apparatus is changed only technically. New Improvements in Telephotography ITH the earlier apparatus of Professor Korn of Munich, it was only just possible to transmit to a distance photographs of faces, busts and landscapes, giving poor results, as the final photograph was not sufficiently clear. On the heels of his improvements, others have also now been announced by a Frenchman, Monsieur Eduard Belin, who first making experiments some months ago in the laboratory of the French Photographic Socienty has since improved his apparatus. The transmitter apparatus of this inventor is purely mechanical. A carbon print in relief of the photograph to be telegraphed is placed on a revolving cylinder; then a fine point explores this, which, by a system of levers and a rheostat, mechanically translates all the variations of relief, modifying with intensity the course of the lines. For the receiving organ Monsieur Belin uses a mirror oscillator which throws on a lens a luminous mark moving from right to left. Against this lens is placed a glass plate called "scale of shades," deepening gradually from right to left, from absolute transparency to black. According to the zone where it is thrown the luminous pencil shades more or less, while the lens, on whatever point of the latter that it falls, leads it back to the same fixed point where it impresses the photographic paper. This paper is mounted on a cylinder which moves in front of this point with a rotary action by means of strong helixes. In comparing the results obtained by the methods of Professor Korn and of M. Belin it may be stated that, while the Korn photographs are spoiled by his luminous ray transmitter only exploring the photographs to the extent of half a millimeter, M. Belin can, thanks to his mechanical arrangement, have a luminous mark as small and a furrow as deep as desired. Thus it will explore the photograph to the sixth of a millimeter. This gives the prints a much greater clearness, which further augments the disposal of the receiver, leaving the luminous ray entire; whereas in the Korn system the interposition of the aluminum plate with the cord galvan A ometer weakens it noticeably. In consequence, M. Belin can, with his apparatus, transmit equally well any kind. of photograph, portrait, or landscape, without a flaw. Finally, it may be added that the Belin apparatus allows of the photographs' being enlarged in transmission. All that is necessary for this is to replace the receiving cylinder by another of larger diameter. In the same way it is possible, by simply reversing the scale of shades, to obtain on the receiver a photograph the reverse of that on the transmitter, either a positive print with a negative or vice versa. Bas-Reliefs by Photography By J. B. VAN BRUSSEL NOTHER curious step, recently made in photography, is that of photosculpture, whereby bas-reliefs are produced by the aid of the camera. A young Italian engineer, Carlos Baese, is the inventor of this very interesting process. The principle of the invention is based on the fact that gelatine made sensitive to light by the addition of bichromate, when immersed in water will lose its capacity of swelling in measure corresponding to the intensity of its illumination. This phenomenon at first sight would seem immediately to afford a solution of the problem, as the substance in question produces of its own accord a relief, whose depth depends exclusively on light intensity. In fact, a negative plate allows all grades of light intensity to be produced, so that a relief of any desired depth can be obtained. However, such a plate, in order to achieve this result, should be more or less transparent, ac cording as the corresponding portions of the model are more or less in relief, and ordinary photographic negatives do not comply with this condition. There are in fact two disturbing factors. For one thing, color is bound to exert some influence on the photographic record, so that surfaces in the same plane will come out with different intensities according to their tint. On the other hand, the light effects of an ordinary photograph depend glass prism or wedge of small angle, the thicker portions absorbing a greater amount of light, and the thinner portions allowing more light to pass. This graduated illumination is made to strike the model to be reproduced in the shape of a plastic photograph. If the model be photographic with illumination, owing to the two disturbing factors just mentionedthat is, the color and inclination of the surfaces-the graduation produced by the wedge will be practically lost. If, however, another negative be taken after inverting CARLOS BAESE. Inventor of the "photosculpture" process. chiefly on the angle of incidence upon the different parts of the model. The same beam of light which, when striking a surface at right angles illuminates an area of say one square inch, obviously lights up a far greater surface when arriving at an angle, and as the same amount of light is used for illuminating surfaces of different sizes, the intensity of the illuminations must vary as the size and hence the inclinationof the surface. the glass prism, and, accordingly, the direction of this graduation, those portions which formerly had been struck by the strongest light will now be in a half-shadow, while the remaining portions will be more intensely illuminated. However, this second negative will for the same two reasons fail to show graduation of the prism. Now it will be noticed that the two negatives, while comprising the given light graduation in opposed directions, are affected by the two disturbing factors in accurately the same sense. Again, as is well known, a photographic print will be darker, as the corresponding points of the negative plate are brighter or more transparent. These facts are utilized by Baese in making from one of the two negatives a positive glass print, which obviously is the reverse of the original negative both as regards light graduations due to the glass wedge and the disturbing factors just referred to. Whereas the two negatives with reversed light graduations have identical defects, the positive plate shows the same light graduations and reversed defects. The two plates can obviously be placed one above the other so as to accurately register. When inspecting this combined picture as a transparency its capacities will be seen to be added, while the defects due to the two disturbing factors are accurately compensated. The combined picture-which for all practical purposes can be regarded as a single picture-now complies with the requirements that its transparency vary directly with the relief of the model and independently of the color and inclination of its surfaces. It can accordingly be utilized for obtaining photographic bas-reliefs on a bichromate gelatine plate. When the gelatine is exposed below the combined. plate, the relief forms very rapidly. As soon as a sufficient relief is obtained the process is discontinued when the model can be used for manifolding by any of the well-known mechanical or electrochemical processes. Instead of exposing the whole model at the same time, it may be illuminated in sections, reproducing each to a given depth of relief, viz., about one-half inch. A convenient com MR. BAESE BEFORE HIS APPARATUS IN HIS PHOTO-SCULPTURING ROOM. A circle of mirrors focuses a strong light upon the subject to be reproduced. |