Journal of the Society of Motion Picture and Television Engineers (1950-1954)

abroad, by Ilford in England and of special emulsions produced by individual investigators, considerable use is being made of photographic techniques in nuclear research. Much of the literature deals with the application of these techniques in such fields as cosmic ray, particle disintegration, particle energy and similar studies. Refinements in autoradiographic techniques have been reported and applications appear to be quite widespread. Work is continuing on the refinement of cloud chambers with a continuously sensitive cloud chamber being reported.286 Characteristics of nuclear photographic emulsions, the techniques in which they are used, and the means for studying the results were subjects for a number of papers. (See Section O above.) One unusual application concerned itself with the study of bird flight. 287 An apparatus measuring 8 mm by 5 mm, is attached to a bird. The device consists of a tube containing an annulus with a source of alpha particles at one end, a piece of photographic emulsion at the other, and a steel ball between. This device is established in such a manner that when the bird is in flight, there is a clear passage between the alpha-particle source and the emulsion, and when not in flight, the path of the alpha particles is blocked by the ball. Data on flying time may be deduced from photometric measurements of the emulsion. U. Miscellaneous A new apparatus permitting simultaneous and instantaneous photography of a 360° panorama was described by Blet288 in France. Two silvered cones are oriented axially with the apexes facing. The image is reflected by the upper cone to the second cone and thence to a strip of 3 5 -mm film held in a glass cylinder arranged about the second cone. In the image produced, the ordinates are amplified relative to the abscissas which proves advantageous in applications for which the device was designed, such as the measurement of sunlight variations with hour of day and season. A device for automatic exposure control designed for the U.S. Air Force was disclosed by Bruck, Higgins and Ward289 of Specialties, Inc. The control system consists of an additional lens and a photocell whose output is amplified to drive a servomotor geared to the camera-lens aperture. The device has a rapid response and is said to be particularly useful for aerial photography. Photographic methods for production of optical gratings and reticles have been proven of considerable use. Two good survey papers were presented in 1950 by Leistner290 and by Gundlach and Rzymkowski.291 The Ansco-Sweet-MacBeth color densitometer introduced earlier was described in this Society's JOURNAL by its designer,292 while Morrison and Hoadley293 of the Kodak Research Laboratory disclosed their spectrosensitometer. This latter device is designed to expose photographic materials through the range of 3500 and 9500 A for the evaluation of spectral sensitometry. The sensitometric steps are produced with repetitive increments of radiation level of log 0.3. A qualitative technique for rendering lines of magnetic force visible was introduced.294 The pole pieces of a magnet are covered with a suitable insulating material containing a few holes or slits. They are connected to each other by a tube containing an anode and cathode necessary for electrical gas discharge, which, under suitable pressures, becomes visible along the lines of force originating from the uncovered points on the surfaces of the pole pieces. Another qualitative technique, this one making ultrasonic waves optically visible, was devised in Germany by Schreiber and Degner.295 A ZnS-CdS phosphor is used of unknown phosphor content. After exposure to light for intervals between 30 sec and 5 min, the resulting phosphorescence is extinguished at the areas of maximum absorption of ultra 476 November 1951 Journal of the SMPTE Vol.57