The international photographer (Jan-Dec 1935)

October, 1935 The INTERNATIONAL PHOTOGRAPH F R Fifteen date. The photographer can make contact prints of his negatives, and from these contact prints select those from which an enlargement is to be made. The contact prints are then mounted on the page of a loose leaf book, the number of the negative and the date being entered on the page. This is really an efficient filing system. In this manner, the photographer can always refer to his book of contact prints whenever it is desired to make an enlargement of a particular subject. Enlargements of each negative will not be required, which means that more time can be devoted to filing away the rolls of negatives, instead of having them lie about, waiting their turn to be printed. Pictures of the Moon: A question has arisen in the case of an ama'eur who attempted [o photograph the moon, giving 30 minute exposures, and instead of obtaining a round image of the moon, the negative revealed a streak. This is not the fault of the camera, film, developer, etc. Mother Earth is the one to blame. Let us go back to our grammar school days for a moment. The earth is continually revolving about its axis, which is responsible for the sun rising in the morning, traveling across the sky during the day, and setting as evening approaches. This is also true of the moon; it is continually moving across the sky which accounts for a streak being produced when a time exposure is made. Shorter exposures are necessary, which calls for both fast films and lenses. A Guide to Enlarging: One of the things left to the judgment of the photographer in enlarging is the choice of the type of printing paper for the negative being enlarged. To facilitate matters the photographer can obtain from his dealer a chart containing the different types of negatives, i. e., thin weak negatives, contrasty negatives, etc., and listing the kind of paper to be used for each type of negative. The photographer merely has to compare the negative to be printed with those on the chart to determine the correct type of paper to use. Removing Dust from Negatives: Dust and small hairs are tremendously annoying at times in printing, causing small spots and white lines on the print. To obtain a print free from such detriments it is necessary to remove the dust and small hairs, and it seems that a diversification of ideas exists as to the ideal tool for this purpose. Many amateurs recommend a soft chamois skin, others a baby's hair brush, or a camel's hair brush that is ordinarily used for swabbing throats, and which may be obtained at any drug store. It really does not mat BY AUGUSTUS WOLFMAN ter which expedient is employed for this purpose, as long as it is soft, so that it will not scratch the film. While on the topic of removing dust, we might mention that before enlarging is commenced the negative should be inspected for finger prints and grease marks. These can easily be removed with a suitable cleaning fluid such as Carbona, Nacto or carbon tetrachloride. A wise procedure is to keep a jar of cleaning fluid with a chamois skin in it continually at hand. In this manner the chamois will always be kept soft and saturated with the cleaning fluid. When Purchasing Chemicals: Amateurs are prone to forget that many chemicals are supplied in different forms such as crystal form, dried form, etc. When purchasing chemicals the photographer should refer to the formula to find the type it calls for. Thus we may take the case of sodium sulphite. The crystal form contains only about half the amount of sodium sulphite as is contained in the dry form. To use the crystal form when the formula calls for dried sodium sulphite is akin to using half the amount of the chemical required; unless the photographer is acquainted with the "strengths" of the two forms of this chemical, and uses the proper larger quantity of crystals in a formula calling for the dried form. Slow-Motion Pictures Help to Check 'Rough Riding" on Super-Fast Trains a regular and continuous motion. The only difference noticeable in the movies of the two wheels was the less violent action of the new wheel due to the fact that this wheel had less clearance between flange and rail than did the worn one. This led to the belief that the oscillation was caused by the taper of one inch in twenty which has been a part of the standard design for railroad wheels. On this belief, a set of wheels was turned without any taper but with the flange kept the same shape and size as formerly. Slow-motion pictures taken of these wheels showed no regular oscillation at all; in fact, the flange seldom impinged upon thy rail on a straight track. The riding of the car was greatly improved, as there was no more nosing. The test car was put into regular service and watched as to wear of wheels and riding quality. The wheels wore with some taper due to the rails being worn that way by the standard wheels, but slowmotion pictures taken after 30,000 miles showed only a slight tendency toward oscillation. This car is still in service and is being carefully watched, but the results of the test have been so conclusive that all new wheels and those re-turned are of the new type without a taper. Says a Chicago, North Shore & Milwaukee Railroad official: "A number of railroad men from other lines have viewed the slow-motion pictures and have applied the principle to their equipment, especially in the case of the new streamlined trains, and greatly improved riding has resulted." Motion Picture Camera mounted to "shoot" moving wheel of oscillating speed-train truck. How smoothness of riding for passengers of super-fast trains, of the streamline and other modern types, has been improved as the result of studies made by slow-motion pictures is an interesting story of American business and its use of scientific methods. About a year ago, the Chicago, North Shore & Milwaukee Railroad, the high-speed electric line running between Chicago and Milwaukee, decided to conduct an investigation of track oscillating or "nosing" — a transportation factor which, because of its contributing to uncomfortable riding, has become increasingly objectionable on all railroads as speed has been increased. A slow-motion 16 mm. Bell & Howell motion picture camera was mounted in a box on a bracket on one corner of a truck which was guilty of nosing. Solenoid control started the camera after the car had reached a speed above 60 miles an hour, when noticeable nosing commences. The camera was focused on the lower part of the wheel where it contacts the rail, and pictures were taken of a worn wheel as found in service and then a new replacement wheel. When the films were projected both the worn and the new wheel were seen to oscillate with Please mention The International Photogra coin • Lenses for every purpose. • Filters of Modern Design. • Exposure Meters. • Reflex Focuser. • Effect Device and Mask Box. • Shutters. • Beira Miniature Cameras. • Film Cameras with Goerz Lenses. Literature on Request C. P. GOERZ AMERICAN OPTICAL CO. 317 East 34th Street New York pher when corresponding with advertisers.