International projectionist (Jan-Dec 1958)

IETTERS TO THE EDITOR In Again, Out Again To the Editor of IP: This focus problem, as discussed by Willy Borberg in his article "Gate and Shutter Characteristics" in IP for June last (p. 14) : While running down the leader of a new Universal newsreel trade-mark there appeared a film flutter at the framing aperture (don't, please, blame this upon the upper loop) of a Simplex X-L which, as you know, has a flat projector gate. Naturally, each time this occurred there appeared an image on the screen which could only be described as "focus flutter". Intermittent at Fault? Proper procedure dictated that I observe the position of the intermittent sprocket each time the film frame at the aperture moved away from the "zero" position. This tricky flutter seems to be prevalent in Universal newsreel prints when the projector motor is turned on and off, which allows the mechanism to "coast" until the eye can discern the film frame moving away from "zero" position and at the same time note the position of the intermittent sprocket. Evidently, on the pull-down the film would go quickly to zero-plane flatness — or beyond to a negative buckle and, then, just as fast to a positive buckle after the intermittent sprocket just finished its travel. I believe that the film inertia between the perforation edges (illustrated beautifully by Borberg in Fig. 3, IP for June, p. 14) could be attributed to the present design of the intermittent sprocket. Weak film, misalignment of perforations, and hold-back friction are major contributing factors. William Palumbo Niagara Falls, N. Y. NOTE: The film-buckling effect observed by Mr. Palumbo at the framing aperture of his X-L's when "running down" leaders is not the same as the heat-induced film flutter studied and described by Borberg in the article titled "Gate and Shutter Characteristics." This writer has often observed the film to "snapin-and-out" over the aperture when running down by hand. But subsequent examination of the film always revealed the presence of some degree of "warp" caused by film-flute (middle of film shrunk more than edges) or permanent buckle (shrunk perforation margins) . This Business of 'Fluting' Fluting of new prints is usually caused by loose winding of the freshly-processed rolls exposed to dry air at excessively high temperatures. This is likely to occur in the drying cabinets of high-speed processing machines. When fresh film is wound loosely emulsion-side "in," and subjected to dry air, the undulations of film-flute alternate from one edge to the other; if the film be wound emulsion-side "out," the undulations are directly opposite one another. (See Mitchell's Manual of Practical Projection, pp. 19 — 22.) Both flute and buckle result in focus-flutter when the film is projected, but the effect is somewhat independent of the shutter-caused rapid flashes of radiant heat which have been so skilfully measured by Borberg, and which produce a blurring of the focus even with prints free from deformation. The strain patterns in film postulated by Borberg appear very reasonable, considering that the film is pulled down through the gate by its edges. Strains of this character are produced in all film, of course; but the presence of flute and buckle deformations would induce such structural strains to force the middle of the film "in" or "out" during the time of maximum pulldown velocity. The middle of the frames do not necessarily return to their original positions when the pulldown-force is removed. In the case of undeformed film, the effects of heat-induced expansion and contraction of the emulsion appear to be almost completely independent of any strains present in the film base during the actual intermittent pulldown. Intermittent Absolved We do not believe that the "design" of the intermittent sprocket, per se, can be blamed for film flutter, inasmuch as the same flutter effects are in evidence when claw movements without auxiliary registration pins are used in place of geneva sprocket movements. Holdback friction (gate tension) is surely an important factor in the production of mechanical instability of film positioning over the aperture, as Mr. Palumbo points out. There is no evidence, however, that the raw-stock manufacturers ever issue film having misaligned or otherwise faulty perforations. OBITUARIES Lorentz, Albert E., 64, and Irvin Turner, 61, both veteran members of Local 171, Pittsburgh, Penna., died within a few weeks of each other. Lorentz, who died after a short illness on August 17 last, was a member of the Local for 43 years and for the past 20 years was a projectionist at the United Artists Penn Theatre (formerly Loew's Penn Theatre) . Turner, a member of the Local for 25 years, drowned in Deep Creek Lake (Md. > where he was spending his vacation. • • • Doerr, Charles, member of Toronto Local 173, and projectionist at the Paramount Film Exchange for the past 37 years, died suddenly last July 17. • • • Mulcahy, William, J., 79, retired member of St. Louis Local 143, died last month. A member of the Local for 48 years, Mulcahy worked in a number of St. Louis theatres until his retirement in 1945. He is survived by his son, James W. Mulcahy, also a member of Local 143. • • • Sands, Mort J., veteran member of Los Angeles Local 150, died August 1 last. A staunch unionist, Sands served the Local in many official capacities. For 25 years he held the office of secretary-treasurer, resigning in 1944. He served as vice-president in 1949-50; was chairman of the board of trustees in 1953; and in 1957 was elected president, which office he held at the time of his death. For many years he represented Local 150 as delegate to the Los Angeles Central Labor Council, State Federation of Labor, and IA Conventions. The Pedagogues, Too The information contained in this Manual of Practical Projection, by Robert A. Mitchell, will be of great use to those of us who administer or operate audio-visual programs. Serious students of projection problems . . . will find much useful information. James D. Finn Professor, Audio-Visual Instruction University of Southern California See back cover. 14 INTERNATIONAL PROJECTIONIST • SEPTEMBER 1958