International projectionist (Jan-Dec 1936)

26 INTERNATIONAL PROJECTIONIST July 1936 general, replaces the widely used 8%volt, 4-ampere lamp of similar dimensions. Its low current rating permits operating it on rectifier filter systems of relatively small size and weight. The proportions of the source are such that the lamp operates particularly well with reproducer optical systems incorporating cylindrical lenses as well as with those of the aperture type. The lamp is available with the standard single-contact bayonet base as well as with the new precision prefocus base. The prefocus base makes it possible to Only High Intensity Arcs Give HIGH INTENSITY PROJECTION H. C. 10 Super Intensity Lamp Descriptive booklet on request. Write for it to HALL & CONNOLLY 24 Vandam St. New York, N. Y. Genuine Simplex Oil YOUR INSURANCE AGAINST MECHANICAL TROUBLE CONSTANT VISCOSITY INSURES CONSTANT PICK-UP PERFECT CHANGE-OVERS Much Cheaper In The Long Run UMTinilMI THEATRE SUPPLY COMPANY ? u:iii«ju:i position the lamp correctly in the optical system by merely inserting it into its special socket. This is a particularly valuable feature for portable and semiportable equipment when the usual skilled operators are not available. The lamp is applicable also to a number of 16-mm. sound-picture projectors. In connection with their studies of various types of recording and reproducing lamps for sound-picture work, the General Electric Co. have developed a special form of microphotometer which makes possible the measurement of brightness distribution across the scanning-beam as well as the total scanningbeam brightness for various types of optical systems and lamps. This company has recently placed upon the market a compact, inexpensive foot-candle meter, which should prove valuable to theatre servicing organizations for checking screen and auditorium illumination, etc. Zeiss has brought out a new series of projection objectives for theatres, the focal lengths of which range from 120 to 180 centimeters. The mounts are either 80 or 100 millimeters in diameter. Notes on The S.M.P.E. Progress Report The foregoing report invites comment in several particulars. Noteworthy is the fact that practically all of the advances cited, particularly those affecting projection, were described in detail in these pages almost as soon as they became known. The Pola-Screen is the subject of a detailed statement elsewhere in this issue. Gaseous conductor lamps, commonly known as mercury-vapor lamps, have been discussed herein, with competent opinion holding that this development still is far removed from application to practical projection work. The Kodachrome color process of Eastman (which firm has a working arrangement with Technicolor) augurs well for the early arrival of a satisfactory threecolor process. Sound recording and reproduction benefited enormously through the introduction of push-pull recording (and now reproduction) by RCA, and the pending plans for widespread use of multi-cellular speakers. The necessary modifications of RCA soundheads for the reproduction of push-pull recordings are detailed in an article elsewhere herein. The Erpi 'Kinetic Scanner' Again Special comment is due the mention of the Erpi Type 209 reproducing equipment designed for small theatres. This unit employs the "Kinetic Scanner," the development of which I. P. considered as an effort to approximate the RCA Rotary Stabilizer (I. P. for April, 1936, p. 24). This "Scanner" is surrounded with considerable secrecy, it appears, since I. P. has been unable to learn of any theatre which kept this unit in for long. A paper on this unit scheduled for presentation at the Spring, 1936, meeting of the S.M.P.E. was cancelled a week prior to the meeting. It is reported that no little difficulty has been experienced by Erpi in obtaining approval of this unit by fire authorities in the field. — Editor.