American cinematographer (May 1930)

May, 1930 American Cinematographer Nineteen ^OUND "Printing o^ttachment for "B. & H . (Continuous "Printer By Joseph A. Dubray I I f i' CONTiNUOUS PRINTER I N ORDER to fulfill the technical and commercial exigencies imposed upon the motion picture laboratories by the advent of sound pictures, it was found necessary to devise means by which the accurate and rapid printing of the sound negative could be conducted independently from that of the picture record. The well known characteristics of sound recording and re- producing demand an extremely smooth and continuous mo- tion of the film in front of the scanning slit, as well as a perfect control of the sources of light which impress the film upon which the sound record is registered or excite the photoelectric cell in the process of reproduction. The meticulous care with which a film sound record is made would be of no avail if the printing process of the sound negative could not be con- trolled with equal certainty and accuracy. From the early in- ception of sound pic- ■ tures, it was evident that the Bell Howell Continuous Printer answered all the requisites of sound pictures, be- cause through years of patient research it had reached such point of develop- ment that all the re- finements ^ost ap- propriate to take care of absolute film registration were in- corporated in it. It remained to devise means by which the printer could rapid- ly and with least in- convenience to both laboratories and pro- ducers be made adaptable to the new conditions. The Bell ^ Howell engineers happily solved the problem by designing a Triple adjustment sound printing attachment which can be adapt- ed to all Bell W Howell printing ma- chines in existence, and, of course, to all apparatus being manufactured. In order to fully appreciate the prob- lems involved and the unique manner in which they were solved, let us sum- marize the require- ments imposed. (1). It was de- sirable that existing equipment could be used. (2). The sound attachment should preferably require on- ly nominal altera- tion and fitting. <',3). Definite BELL &-HOWELL WITH TRIPLE ADJUSTMENT SOUND ATTACHMENT FIG. 2 FIG, FIG.4 FIGS FIG.6 ■A* 'B' & 'C' - SHUTTERS MASKING SOUND AND PICTURE AREAS. 'L' - SHUTTER OPERATING LEVERS 'S’ - PAWL TENSION SPRING . ’P' - shutter LOCK PAWL FIG. I - MAJOR DETAIL OF B8.H PRINTER - WITH GATE REMOVED. FIG. 2- THE TRIPLE ADJUSTMENT SOUND MASK ATTACHMENT - INSTALLED. FIG, 3- THE TRIPLE ' ADJUSTMENT SOUND MASK ATTACHMENT FIG.4- SHUTTERS RETRACTED FOR FULL APERTURE PRINTING FIG. 5 - SHUTTER A' SET FOR MASKING THE SOUND AREA - FORWARD RUN FIG 6 - SHUTTERS 'B’&'C SET FOR MASKING PICTURE AREA - FORWARD RUN FIG. 7- SHUTTER 'C SET FOR MASKING THE SOUND AREA - REVERSE RUN FIG 8 - SHUTTERS 'A'& 'B' SET FOR MASKING PICTURE AREA - REVERSE RUN light control for printing the sound and picture portions inde- pendently should be insured. (4) . If possible, the attachment should permit printing either the sound or the picture area from either end of the roll, to eliminate waste time in rewinding. (5) . It was desirable that it comply with the standards ap- proved by the Society of Motion Picture Engineers, whereby a black light shield is to be printed along the sound track to eliminate any possibility of variation of tone in sound repro- duction due to a possible side motion of the film in front of the scanning slit of the projection apparatus. (6) . The device should be convenient, quickly set at any desired adjustment, positive and accurate. (7) . It was desirable to have the masks arranged so that the full negative ; (for silent pictures) could be printed at one adjustment. The following de- scription will ex- plain clearly how very effectively the Bell Howell Com- pany have solved this problem, and the figure illustrating this article will clearly il- lustrate the workings of the attachment. At 1 and 2 the triple adjustment sound attachment is shown installed in the standard Bell Howell Continuous Printer. The attach- ment itself consists of two main assemblies —the masking unit and the operating lever unit. The masking unit is installed in place of the usual top aperture plate. After it has been accurately adjusted in the print- er, a hole is drilled through the top of the printer casting into the masking unit, and tapped. This insures the masking unit always being held in perfect align- ment. The operating lever unit is then in- serted through an ac- curately milled slot in the printer casting so that the levers en- gage the masks prop- er. The operating unit is then fastened permanently in posi- tion. At 2 is plainly shown the manner in which the sound at- tachment is arranged. (Cont. on Page 22) FIG. 3 FIG. 7 FIG.8