The Educational screen (c1922-c1956])

Page 394 Educational Screen The ABCs of AudioVisual Equipment Film Inspection: Key to Showmanly Educational Exhibition IT is a familiar old saw that a chain is no stronger than its weakest link, yet, when the components of the audio-visual program are regarded as links in a chain keeping the student well-tethered to the solid rock of reality, the significance of the simile is obvious. Adequate administration and supervision, proper selection and utilization of materials, the materials themselves, and the mechanics of projection serve as important links in connecting instruction with reality. In the area of motion picture usage, the simple, unimpressive film base is often the weakest link in the program. Selection may be adequate, utilization fine, and projection splendid; yet the film itself, committed to an existence of jerky rollercoaster rides through the projector, is afforded little more attention than frequent rewindings on unyielding reels. And the film itself, you know, in addition to varied emulsions carried on its surface, is pretty important. Suppose the film breaks ; hmmm ? Then, where are you ? The world you brought into the classroom vanishes out the window, and a lengthy ribbon of cellulose acetate is all that remains. Selection ? Utilization ? For what ? To acquaint your pupils with technological failure? Yes, let's put it that way . . . let's not harbor any suspicions about the efficiency of a director, who thinks that film direct from the exchange may be slapped into the projector — and perfection result. Handing an instructor or a student operator a reel of uninspected film is running the risk of sabotaging the instructional eflfectiveness of that class hour. "Well, what do I do,'' asks the conscientious director, "preview all our films in advance of showing?" No, that's vmnecessary, although teacher previews may well be the means of checking a number of the films to be used. Instead, provide the audio-visual workroom with a good set of hand rewinds firmly attached to a lower-than-average table equipped with adequate illumination, secure a precision splicer, and train a sharp-eyed clerk for the job of film inspector. Film inspection should occur whenever a film is received from an outside source for use. If the school has a film library of its own, inspection should be made following every series of showings before it is returned to its cabinet or rack. Then, the staff may be sure that when the film is called into service again, it will be ready to perform its task without endangering itself or the instructional program. Specifically, the first step in examining a reel of film for possible flaws is to look at the "leader", which should be about six feet in length and without tears or torn sprocket holes. In addition, it should be opaque throughout the foot or so of its length immediately preceding the opening titles. The remainder may be dotted with "Academy numbers", although, to oflfset Edited by ROBERT E. SCHREIBER the possibility of some eager projectionist's switching on the lamp too soon, it is better to have it opaque throughout. A supply of opaque "leader" film is preferable in providing adequate leaders than a collection of odds and ends. In addition to the much-abused leader, the title length of the film should be minutely inspected, since it is in these two areas that faulty threading encourages most film damage. Having followed the course of the usual film damage through the leader, the titles, and the opening scenes of the picture, the inspector may advance more rapidly through the reel, but he continues to check the condition of the film by passing it through his thumb and first two fingers. By touch, splices in need of repair or torn sprocket holes may be discerned and repaired. The last stronghold of film damage is found in the last five or ten feet on a reel. This is due to at least two things ; first, on 400 foot reels, the film is wound in such a tight circle around the reel hub that — if it remains thus for some time — it tends to resist straightening while passing through the projector. Second, the end of the film may become tightly wedged in the film hub slot, and the claw and sprockets tear perforations in the efTort to eflfect passage. Following the end title should be another foot — at least — of opaque "leader" film ; more, if the title does not fade out — and several feet if there is no end title at all. Thus far in this discussion we have assumed that the film inspector knew what to do when film damage of any sort was encountered. The mere mechanical act of splicing two pieces of film together is not an art, but it should be done skilfully. A good splice should last the life of the film, but making such a one is somewhat difficult without the use of relatively expensive equipment. Basically, the operation of splicing involves removing the emulsion from one film and with a wet or dry scraper unit so that — in overlapping the two ends — film base contacts film base without any emulsion, dirt, or water intervening. Contrary to popular belief, films are not "glued" together ; welding is a better word, since film "cement" is really a solvent for the film base. When this solvent is applied between the overlapping film ends, the base of each is momentarily softened. Pressure is then applied, and a "weld" approximated. To minimize the pictorial distraction of a splice passing through the projector, it is imperative that the splicer be accurately adjusted so that emulsion is removed only to the extent of the "bonding" area. When the splice is completed, there should be no clear streak across the film. If such exists, the splice is noticeable to the eye as well as to the ear — the light streak on the sound track causing a "bloomp" as it passes the photo-cell. The diagonal splice has been recommended in some quarters on the basis of strength, but it is more noticeable than a straight splice, which has been stan