International projectionist (Jan 1959-Dec 1960)

LETTERS . . . Continued from Page 13 of the Taylor unit would require a retooling of the factories and discontinuance of conventional set-ups. The writer submitted a description similar to this to Mr. Kloepfel in 1959 and received a reply requesting a rough sketch or drawing from which design could proceed. Due to the pressure of other matters we could not find the time to comply with this request, but if Mr. Kloepfel or other responsible party desires a sketch now, we shall be glad to prepare one. J. HARRY COLEMAN The Coleman Electric Co. Toronto, Ontario. COLE.MAN ("TAYLOR") Film PR.OJtC.TOR. ^§^g 4 < Oscillating mi %l£/ <■ Roller plate u Fixe J Light beam EAR.LY JACKS ON PROJECTOR, Editor's note: — A diagram of the Taylor projector as compared with the one built by J. G. Jackson, based upon sketches kindly supplied by Mr. Jackson, is given herewith. Also appended are J. G. Jackson's opinions anent the Taylor mechanism. Editor, IP: Mr. Coleman's description of the Taylor projector is particularly interesting to me, as I also did some experimenting on the very same type of projector. In fact, it was my first experiment with non-intermittent projectors back in 1939. I used a Motiograph Model 1A projector (1912) — the little hand-cranked unit — which I still have in my shop, though having used some of the gears from it in my other projectors, it is no longer complete. I geared the intermittent sprocket to revolve continuously and actuate a cam to tilt the mirror. While Mr. Taylor set his model horizontally so as to use only one oscillating mirror, I set mine upright and used two mirrors, one of them fixed, to put the image on the screen. I soon discarded this type of projector for several reasons, the main one being the low luminous efficiency of the 2-frame aperture. Even with a fast return of the mirror, I found that I got less light on the screen than I did with the intermittent projector. The spot required for a 2-frame aperture has more than twice the area of one for a single frame, hence the luminous flux passing through a film frame is less than half what it would be in a normal single-frame projector. Mr. Coleman also states that no shutter is required in the Taylor machine. This may have been true with a 500-watt mazda lamp; but I doubt very much that the absence of a shutter would be permissable if a highpowered arc were used to provide a high screen brilliancy. I am afraid that travel ghost would show up no matter how fast the mirror returned to its starting position. And, of course, if a shutter were used, the luminous efficiency of the machine would be reduced just that much more. Then, too, I found that light from the unused frame in the aperture flashed to the screen, hitting both above and below the screen. I soon found out that many other inventors had tried out this same idea before, so I abandoned it and searched for a system of my own — an eminently feasible system which the overwhelming majority of responsible projection experts agree is superior to other systems of non-intermittent projection which have been tried out up to the present time. Thanks to IP, the projectionist's own magazine, everyone interested in the art, including projectionists, inventors, and manufacturers, have at their disposal an ideal medium for the expression of their views on all projection topics. Let's hear from others who have done experimental work in the field of projector design. How about it? J. G. JACKSON Port Alberni, B. C. Questions & Answers From Frank W. Mango, IATSE Local 150, Los Angeles, California come the following interesting queries which cannot be answered in all cases as fully as we might wish, but nevertheless serve to indicate the nature of the technical problems occupying the attention of advanced projectionists. Q. Referring to the various optical sound reproducers which have appeared since 1927: are there accurate data available which give honest values of wow and flutter in gate-type heads as compared with the more common fluid rotary-stabilizer types? A. No studies of which we are aware have been made to give these comparisons. However, modern standards are rather definite in regard to sound-on film recorders: if the rate of film travel does not vary from 90 feet per minute by more than 0.05% either way — a total flutter content of 0.1%, — the amount of flutter is considered to be satisfactorily low. Modern theatre reproducers of the rotary stabilizer type are designed for a flutter content under 0.2%, but improper operation can greatly increase the amount of flutter obtained with these heads. However, old gatetype heads often had a flutter content as high as 1% even when in good working condition. Much of this could be attributed to the 96-cycle disturbance caused by the film perforations and teeth of the sound sprocket. Q. What is responsible for the annoying wow and flutter so often heard in 16-mm reproduction? Will you go into detail on various designs of 16-mm optical scanning stabilizer assembly principles? Also, is the flutter sometimes already in the print as a result of accumulation from original recording to final print by way of dupes, etc.? A. Most of the flutter originating in 16-mm projectors is due to (1) inadequate size of the sound flywheel, (2) use of a solid flywheel which, unlike a good rotary stabilizer, returns disturbing forces to the film in the form of low-frequency "wows," and (3) dirt, improper lubrication and other defects of the pressure rollers used in some projectors to insure contact of the film with the scanning drum. Details of the construction of the sound transport mechanisms of the dozens of different makes and models are best obtained from the manufacturers. Flutter is nearly always introduced into 16-mm prints from 35-mm originals by the re-recording process, although with good equipment this should never exceed a total of 0.2%. This small amount of flutter is easily measurable with a flutter bridge, but it is doubtful that the ear could detect it even in tones exceeding 5000 or 6000 cycles. Q. In preview rooms where the projection throw does not generally exceed 60 feet and sheet width is under 30 feet, and where flicker is made more obvious by too much screen light, what were the economic or technical reasons for changing over to the Suprex type of light source? A. The use of low-amperage Suprex ("simplifed high-intensity") arcs in preview rooms instead of Mazda or lowintensity arcs is dictated by (1) economy of operation and (2) daylightwhite quality of illumination suitable for judging the balance of color films. The 7 and 6-mm Suprex trim of carbons may be burned at 40 amperes with an arc drop of 27 Vz volts to give 6500 screen lumens with a mirror 11% inches in diameter. This is only 1100 16 International Projectionist December 1960