The New York State Exhibitor (1933)

YOUR THEATRE JanlO'33 If exhibitors and operators would only be more cautious they would save money for themselves and the industry in general. There is no excuse for defective equipment and poor handling. Proper projection is the nucleus of any theatre. An excessive pull can always be detected by the film making a “singing” sound at the take-up sprocket. The sprocket, of course, acts as a hold-back or brake and puts a strain on the film, when starting on a small hubbed reel. This is sometimes enough to cause very severe damage to the upper side of the perforation. Proper setting of the spring is a simple matter and care should always be taken to keep the friction disc, whether leather, cork or fiber, absolutely free from oil. Contrary to some opinions oil will not cause smoother operation in a case of this kind, but will really create a certain amount of suction which in turn re¬ sults in an uneven, excessive pull. SOME WIDELY USED MAKES OF PROJECTORS have an adjustable spring tension on the upper magazine shaft or spindle. Proper adjustment of this spring is important. If set too loosely the film will come from the feed roll with a jerky motion. This is especially noticeable if used with a bent reel, which is bad for any film, particularly film which is in a dried-out condition or badly worn. ALL SPROCKET IDLERS must be properly adjusted. If set too far from the sprockets, the film is liable to jump out of place and ride over the teeth, whereas, if they are set too close they will ride the film, causing creasing, especially on the lower sprocket which acts as a brake on the fric¬ tion take-up. It has been found that the safest distance to set an idler from a sprocket is the thickness of two pieces of film. Some manufacturers recommend the thickness of one piece of film but this is in¬ sufficient as the distance between the sprocket and idler is too small to allow the average splice free passage. When the idlers are properly adjusted, it should be possible to move any idler from side to side without danger of touching the sprocket teeth. Badly worn idlers mark the film and should be replaced immediately. THE INTERMITTENT FILM GUIDE is for the purpose of holding the film snugly against the intermittent sprocket but other¬ wise has nothing to do with the steadiness of the picture. Filing the openings in the film guide holders is sometimes necessary to insure the proper amount of side clearance for the sprocket teeth. Moving the film guide from side to side while the projector is running will determine whether or not the teeth have sufficient clearance. MANY PROJECTIONISTS have found it advisable to substitute a slightly lighter film guide holder spring for the stiff one furnished by the manufacturers. By this small change, less strain is put on the film at this point, with absolutely no change in screen results, wide and stiff splices, espe¬ cially, going through with greatly decreased resistance, thereby lessening the chance of film breakage due to the yielding of the film guide. One of the main reasons for picture unsteadiness is an excessive amount of play between the moving parts of the intermit¬ tent movement, due to wear. Readjustment is made by means of an eccentric bearing but care must be taken to see that it is not set too tightly, otherwise the parts will bind. SOME PROJECTORS provide for a side adjustment of the intermittent shaft by means of a collar and set-screw. Proper alignment is necessary to insure against the intermittent sprocket striking the film per¬ forations off-center. Excessive wear of the pin-cross type of intermittent movement results in flat sides on the pins, thereby causing a slightly quickened pull-down which gives an added strain on the film perforations. On some models these pins are equipped with rollers insuring smoother operation. ONE WIDELY USED PROJECTOR has an adjustment on the top magazine which allows for its proper alignment. Unless great care is taken to see that the magazine is in line, the film coming from the valve rollers will not feed squarely under the idle roller. This generally causes fractured film to crack from the perforations to the edge of the film. This improper alignment also causes film breaks resulting from film with nicked edges and from loose splices comingin direct contact with the sides of the valve. The idler roller on the same projector men¬ tioned is one-half inch diameter and causes the film to make a sharp turn on itself. On a roller of this size film which has been dried out and thus has become brittle may break, especially if there is an important amount of tension on the feed roll. If trouble of this nature is encountered the substitution of a larger roller, preferably the diameter of a sprocket, namely, fifteensixteenth inch is a practical remedy. This means but a small amount of work, as only a simple extension is necessary to allow the proper amount of clearance and it will be found to be well worth while. EXCESSIVELY LARGE UPPER OR LOWER LOOPS either cause a rattle in the film guard above or allow the film to drag in any oil which may be present be¬ low. The film also has a tendency to jump the sprockets, which can take place if the idlers are set too far from the sprockets. The practice of resetting loops while the projector is running should be discouraged as in many cases the sprocket teeth strike outside of the perforations, or otherwise damage the film. MANY SCRATCHES are caused by worn film tracks, or trap-shoes as they are known on one of the projectors, allowing the face of the film to scrape against the recessed aperture plate. Such tracks or trap-shoes together with all tension shoes or door pads that show a “wavy” or badly worn-down surface, should be replaced by new ones. THE VALVE ROLLERS of both maga¬ zines should always be kept clean. Care should be taken to see that they revolve freely, as the sticking roller can cause bad emulsion scratches especially if it is worn, thereby allowing the center of the roller to come in direct contact with the face of the film. This is especially true of the upper Page 13 E magazine rollers around which dirt and small pieces of film very often accumulate. ON SOME PROJECTORS, so called strippers or stripping plates are provided to prevent, by any ctiance, the film from winding around or “following” the sprock¬ ets as well as to remove any accumulation of dirt that may tend to form at either side of the sprocket teeth. In resetting these strippers after the replacement of sprockets, extreme care must be taken to see that they do not come in contact with the teeth, as this will cause the teeth to wear to a sharp edge which will damage any film coming in contact with it. Flooding the mechanism with oil is unnecessary and causes oil to get on the film. Dust then adheres to the film making good clear projection impossible. This practice also is a nre hazard as oily film will catch fire a great deal easier than that which is clean. Aside from the inter¬ mittent case, one drop of good oil in each oil hole will be sufficient lor the average day’s run. FILM DAMAGE CAN sometimes be more easily traced if it will be remembered that certain projectors run the film emul¬ sion or dull side against all three sprockets, while on others the support or shiny side, only touches the sprockets. For example; if nlm is received showing tooth marks on the emulsion side, it is fairly simple to de¬ termine on what make or makes of projec¬ tors this film has been run, especially if the investigator has familiarized himself with the different types of sprocket teeth. IN CONCLUSION, special attention is drawn to the desirability of waxing new prints along the perforations to prevent un¬ steadiness and premature breakdown. In making the light-sensitive emulsion of mo¬ tion picture film one of the chief ingredients is gelatin — a substance which readily ab¬ sorbs and gives off moisture. In freshly develoDed film the gelatin contains a consid¬ erably higher percentage of moisture than is found in seasoned film, and when in this condition it is easily affected by heat, tend¬ ing to make it soft and tacky particularly in a moist atmosphere. The first point at which new film comes in contact with un¬ usual temperature is at the aperture plate of the projector where the light is concen¬ trated, producing heat to a degree which softens the gelatin and causes it to collect on the tension springs or shoes where it rapidly dries and forms a flint-like deposit. As the new film is projected, the hardened deposit of gelatin continues to accumulate and offers further resistance, causing scratches along the perforations. As the resistance increases there is the added danger of the teeth of the intermittent sprocket tearing and damaging the perfo¬ rations, sometimes to an extent where injury to the print is irreparable. CAREFUL WAXING PRODUCES, under the action of heat, a smooth and polished surface on the gelatin along the perfora¬ tions ; provides against undue straining during the first projections of new prints; materially benefits successive runs, and greatly prolongs the commercial life of the prints. Cold wax should never be used as it is impossible to apply it evenly. There is also the danger with the cold method of over-waxing with the result that, in contact with the heated pressure springs, the wax melts and spreads over the picture. A very slight application is all that is necessary and is best accomplished by a waxing ma¬ chine which deposits a thin layer of hot wax along the perforations. New prints treated in this manner require no further waxing.