International projectionist (Jan 1959-Dec 1960)

Silicone— Treated Cloth? By JAMES J. FINN SILICON E-TREATED cloths represented as having a wide variety of useful applications in the projection field have been the topic of numerous letters received recently by IP, so much so that IP feels impelled to express its opinion as to the various uses of this product suggested by the manufacturers thereof. IP absolutely disapproves of the use of silicones on motion-picture film, lenses and phonograph records. However, even though silicones leave a mottle on film, they may possibly be used with benefit on filmstrips because the film remains in contact with hot glass pressure plates during projection. Use of a silicone cloth in this application may prevent sticking and emulsion damage. It should be obvious that both the filmstrips and the glass pressure plates will require frequent cleaning when silicones are used. In any event, IP' is not sure that it should wish to recommend a silicone cloth even for this purpose. Use of silicones on films of any kind that may in future be duplicated by contact printing is harmful. Raw stock is mottled and fogged by silicones, according to Eastman Kodak Co. IP has had tests made of such cloths on film, phonograph records, the film gates of projectors employing highiiitensity arcs, and various other units in projection rooms, in addition to the treatment of film under special conditions. These cloths cannot harm, nor much help, release prints unless too much moisture is applied to the cloth, and it may be useful to prevent, or minimize, the "sticking" of "green" prints. However, if the film is not wiped in a continuous manner, there is a tendency for such cloth to leave an oily streak or mottle on the surface. Use on Lenses Unthinkable Under no circumstances, however, should silicone-treated cloth be used on raw stock or on negative or masterpositive printing films. Important To Projectionists: The use of silicone cloth on camera or pro Are You Moving? If so, please notify us one month in advance. The Post Office does not forward magazines. To avoid delay, please cooperate by sending us both your new and old address. jection lenses is unthinkable. All lens manufacturers warn against such usage on coated lenses for the simple reason that a layer of silicone or any other kind of grease or oil interferes with the proper optical functioning of the magnesium fluoride anti-reflection coating. Such coatings are designed to work efficiently with glass on one side of them and air on the other. The use of silicone cloth neither guards against the brittleness of film nor fading of the photographic image. The statement that the cloth add"depth, brilliance to color or black-andwhite-film" is unfounded. Silicones are incapable of acting as intensifiers oi reducers, though it may be assumed that the removal of dirt from the film improves the quality of the image. Photo filters should not be treated with -illcones, especially if the filters are antireflection coated. Not a Dust Resistant A silicone coating on film or phonograph records does not prevent the collection of dust. In fact, dust adheres more readily to silicone-treated film than to clean, dry. unlubricated film. The lor the PRIME IENS *«■ ^ # 8 out of 1 0 Exhibitors today choose a Kollmorgen Super Snapiite for their prime lens. Perhaps this is because for more than thirty years Snaplites have been the standard by which all other lenses have been judged. For speed, for contrast, for definition and for terrific brilliance on the screen, your 1 st Choice is a Super Snapiite. Write for Bulletin 222. ILOIiliAlOltOKN \SpUCGU, « o it ■• o it *k/r ■ m m 'NORTHAMPTON, MASSACHUSETTS INTERNATIONAL PROJECTIONIST FEBRUARY 1959