International projectionist (Jan-Dec 1937)

16 INTERNATIONAL PROJECTIONIST October 1937 visions are adopted by the industry is of little moment at this time; but the Council is fulfilling its primary function in this matter, as in all others with which we are concerned, in acting as a clearing house for the industry in carefully investigating all matters in connection with any technical change in advance of making that change. Not 'Selling" An Aperture "The Council is not 'selling' an aperture either larger or smaller than the present aperture, but is only concerned with getting the best possible aperture for use in the industry. Stories in the press have been brought to our attention carrying figures purported to indicate the costs to the theatres of revision . . . These indicated costs, in my opinion, have been grossly exaggerated. "In addition, the revision proposed by the Council, is approved by all concerned and eventually adopted by the industry, is very flexible and will be optional with any theatre. Those thea tres which may not wish to expend the small amount of money necessary to purchase and install aperture plates of the new dimensions and alter their screen masking, may continue as at present; but those theatres which may wish to take advantage of the new improvement may do so at a small cost by installing new plates and remasking as their screens are cleaned or renewed. "Our Committee . . . will continue its consideration of the matter . . . Upon the conclusion of consideration of all technical opinions submitted by representatives of studios, equipment companies, commercial laboratories, theatre circuits and other technical organizations, including of course the S.M.P.E., the Committee will submit their findings to the Council . . . "If approved by the • Council, these recommendations will then be transmitted for action by the proper authorities concerned with a change in equipment such as is involved in this case." Letters to the Editor Insists That Aperture Heat Influences Manpower It is not my intention to prolong the discussion of aperture heat. The matter will not be mentioned again. I feel an urge, however, to defend the presumption that the subject has some tearing on manpower. My only contact with the industry outside this remote locality is through I. P., God bless it. Naturally, I. P. forms my opinion on many questions, including impressions of what factors are important to projection men throughout the country. From time to time you have mentioned, with obvious satisfaction, certain legislation making two-men shifts a requirement. I conclude that, regardless of the feeling that there is good reason for voluntary return to two-men shifts, tbe projectionist fraternity approves of such legislation and would welcome more of it. It occurs to me that the consideration back of these laws must be safety. The lawmakers' only object, I presume, is to reduce the possibility of exposing the public to any fire liazard. If that assumption be correct, the course of action to get more legislation is to call attention to the risk, however ■slight it seems to us who are familiar with it. K. P. Kenworthy Moscow, Idaho. Larger Suprex Carbons Now Available, Says Noris Co. Your comments in the "Monthly Chat" column are always read by us with a great deal of interest. There is one paragraph in the September "Chat" about which we have some comments to make. The paragraph states: "No larger Suprex carbon combination will be forthcoming soon, at least not within the next year." This is emphatically not so. As long ago as September, 1935, we brought samples of larger Suprex carbons into the United States at the request of one of the larger lamp manufacturers. The positives were 8 mm., 9 mm., and 10 mm. in diameter and were 16 inches long. The negatives were 6 mm., 7 mm., and 8 mm. in diameter, respectively, and 9 inches long. These trims functioned perfectly as far as light and burning time were concerned, giving approximately 12% to 15% more light than a standard 8 mm. Suprex trim, at an increase in current of from 5 to 10 amperes over the usual 65. The only factor to be perfected at that time was straightness of the positives. The extent to which these larger Suprex carbons of ours have been improved since that time is best illustrated by the fact that we are now supplying 9 mm. by 20-inch Suprex positives together with 7 mm. x 9" negatives. These carbons are giving an excellent account of themselves in this country, and for the past six months have been in daily use with great success. We will be glad to show you samples of this trim. The salient features of this 9 mm. x 20" Pos., and the 7 mm. x 9" Neg. Suprex trim probably will be interesting. This combination is rated at 75 to 80 amperes, but can be boosted without any trouble as high as 100 amperes, in which case the light intensity comes within reach of the light produced by 13.6 mm. carbons, using 125 amperes. Of course, if the maximum of 100 amperes is used, the carbon consumption increases considerably, although it still cannot be called "prohibitive." If, however, this trim is burned at its normal rated amperage, it will give an increase in light of about 17% to 20% over that produced by a standard 8 mm. positive 7 mm. negative Suprex combination. Conclusive tests have furthermore shown that the ratio of carbon consumption is approximately 1:2.5 in comparison with a 12" positive carbon. This favorable ratio is achieved first, by the construction of the carbon itself, and second, through the elimination of carbon waste (stubs) due to the extra, added length of eight inches. Since the price of the 9 mm. x 20" Suprex positive carbons is by no means excessive, and since the carbon shows such decided advantages in operation, this trim can under no circumstances be called an oddity or an experiment. The point we wish to emphasize is that a larger Suprex trim is practical; that a larger Suprex trim is on the market and has been for quite some time. Noris Carbon Company E. W. Schumacher, Manager The information relative to Suprex carbons which appeared in last month's Monthly Chat, and referred to in the foregoing letter from Noris Carbon Co., was obtained from and credited to National Carbon Co. This data was published as the well-considered opinion of a reputable company, with the same measure of good faith that prompted publication of the Noris letter. We view the situation as one wherein National having spoken for itself, Noris now speaks for itself — the procedure in both instances serving to emphasize anew the established policy of I. P. to open its columns to anybody and everybody having something interesting to say anent the projection process. Honest differences of opinion, particularly where company policy is concerned, naturally do not involve any question of veracity. — Ed. FILM PERFORATING PROCESS Perforating the film would be comparatively simple if it were not for the extreme accuracy required. The punches and dies are so accurately made that the punches can not be inserted into the dies by hand without injuring them, although when clamped in the machines they go in and out thousands of times without appreciable wear. Each punch consists of eight punching members and eight positioning members, or pilots, four of each on each side of the film. As the film passes through under the punch, four pairs of holes are made. A shuttle then moves the film four spaces forward, and the ram moves down again. This time the pilots, which have slightly tapered ends, enter the holes that have previously been punched, and ^finally position the film before the punches strike the new holes, so that each set of eight holes is accurately positioned by the previously punched set of holes. The tolerance ordinarily used in manufacturing the punches and dies is approximately 0.00002 inch.