Motion Picture News (Sept-Oct 1918)

'September 28 , 1 p 1 8 207 \ C sum e r ct Labor a'Lory JML ctlc irtg Studio Sun-Light Arc, a Super Light-Source for Cinematography RECENT years have seen great developments in high-power searchlights, and a studio arc lamp for cinematography, designed along similar lines, has been perfected within the last two years. This is the Sun-Light Arc, made by the Sun-Light Arc Company, Inc., of 218 West 48th street, New York, which is shown in the accompanying illustration. This powerful light source was kindly demonstrated for us by Mr. J. J. Harmer, of the Sun-Light Company, and an account of its capabilities may prove of interest to our readers. Like its prototype, the modern high-power searchlight, the SunLight lamp utilizes the carbon arc, and one of its most important features is the mechanism for feeding the carbons. In the SunLight lamp the carbons are fed automatically, and the lamp will burn for about one hour without feeding the carbons or any other attention, after which the carbons are entirely consumed and must of course be renewed. It is requisite that a light source used for cinematography be absolutely steady burning The Sun-Light Arc and free from flickering, a difficult requirement to fulfil in an arc, but which is accomplished in the Sun-Light lamp in the following manner : The upper, or positive carbon, bearing the light-giving crater is caused to rotate slowly and steadily by a mechanism attached to the carbon holder, so that a perfect and symmetrical crater is maintained at all times. The upper carbon is also fed downward automatically, and the negative carbon fed upwards, by independent mechanisms. This monster light-source is alleged to furnish an illumination of 100,000 candlepower per lamp, and each arc operates at 150 amperes of direct current. An idea of the power of these SunLight Arcs is gained when Mr. Harmer exhibits, in the demonstration studio of the Sun-Light Company, a motion picture made in the grand ball-room of the Hotel Astor with the aid of only two Sun-Light lamps. This motion picture is*fully exposed and shows splendid detail in every scene, and when the size of the grand ballroom is considered, the power of the Sun-Light Arc becomes readily apparent. On another occasion successful motion pictures were also made of the Motion Picture Directors Association ball, at the Hocel Biltmore, where only one Sun-Light Arc was used. Both this fi'.m and the one made in the Astor ballroom are free from the confusing multiplicity of shadows which are sometimes apparent when a large number of separate light sources are used in lighting a scene. Just recently these powerful light sources have been used in the Metropolitan and the Manhattan Opera Houses, in filming the ensemble scenes for the picture in which Enrico Caruso is to appear. At the Metropolitan Opera House three Sun-Light Arcs were used, while two were employed in the work at the Manhattan. The Sun-Light lamp is also a powerful illuminator when photographing outdoor scenes at night, and by the addition of a parabolic mirror behind the arc an intense parallel beam may be projected a distance of many miles. Mr. Harmer has an interesting photograph showing the giant Woolworth Building, New York City, fully illuminated by a parallel beam projected from a location in Brooklyn a mile and a half distant. The beam is substantially parallel due to the use of the parabolic reflector, and the lighted towers of other neighboring skyscrapers rear themselves above the outline of the path of light. The Sun-Light Arc is mounted on a rigid tripod of metal tubing, as shown in the illustration, and its weight is about 180 lbs. The Sun-Light Company. do not sell the lamps outright but rent them by the day or week accompanied by an operator to install the lamp and control its performance. A smaller lamp of about 50,000 candlepower will shortly be available for industrial work, which will also be exploited on a rental basis. X-Ray and Micro-Cinematography Mr. H. N. Wilkins, Astoria, L. I., inquires: "Which, if any, of the books on cinematography give details of the methods of making the interesting X-ray and microscopical film subjects one sometimes sees? I am interested in learning all particulars of this class of work." In reply: Interesting as the results of scientific research are, when recorded and exhibited cinematographically, there does not seem to be any systematic attempt to produce this class of pictures in the United States, although we must be thankful for the occasional film of this character which comes along. The French, on the other hand, have extensively demonstrated the possibilities of cinematography as a means of recording scientific experiments, and the history of motion pictures shows that the French were scientists in this work from the start, as evidenced by the pioneer experiments of Marey. It is to the French text-books on cinematography that the correspondent must look for information on the production of the X-ray and the microscopical film subjects, although even in those most thorough works the subjects now under consideration have received all too scant a description. In Ducom's " La Cinematographic Scientifique et Industriel," Paris, 1911, there are some pages devoted to micro-cinematography, but X-ray work in connection with the motion picture camera appears to have escaped the attention of the French writers in spite of the splendid showing of their movie producers along this line. In view of the general scarcity of published information on the methods of X-ray and micro-cinematography, the following brief outline of the necessary procedure may be of some interest and service to the readers. Either class of work could be made the subject of an extended article, but on the present occasion we can but glance at the more important details of the respective procedures. In X-ray cinematography the object to be depicted (usually some part of the human body) is rayed in substantially the customary manner, but as the X-rays will not be refracted by a camera objective to form a satisfactory image, a fluorescent, or intensifying, screen is used to intercept the rays passing through the object being studied, and the image projected upon this intensifying screen is then photographed by a cine camera focused thereon. It is in substantially this manner that the successful X-ray motion pictures have been made, but the method is in no wise as simple as the above would lead one to infer, because special precautions have to be taken at every stage. As wood is transparent to X-radiation, the camera must be en