Home Movies and Home Talkies (Jun 1932-May 1933)

280 HOME MOVIES & HOME TALKIES SPLICING YOUR FILM A SIMPLE PROCESS By PERCY W. HARRIS SPLICUCG or joining up a film is a process requiied in all film editing. It is, in point of fact, quite easy to do, aad many de\'ices both simple and elaborate are sold to facilitate the t«sk. There are tluee main requirements in a good splice. Fir-st of all the join shoidd be sound and secure and as strong as the film itself, otherwise before long it will part during projection ; secondh the splice should pass through the jirojector without the join even being noticeable on the screen, and thiidlj the correct distance between the adjacent slotted holes on each side of the join must be acciu'ately maintained. Know Your Material ! To understand how a good sound splice can be made we must consider the material with wliich we are dealing. The film itself consists of a strip of slow-buming, or so-called ■'non-inflammable " celhdoid material on the top of which is spread a layer of gelatine impregnated with certain chemicals. The image is formed and developed in this gelatine film, the celluloid acting merely as a convenient flexible and transparent supporting base. In order to join two jiieces of film it is necessary that one piece should overlap the other shghtly. This means that if we gave no sj^ecial treatment to the film the plain celluloid siu-face would be brought into contact with the gelatine covered siu-face, and, if it were possible to fix the celluloid firmly on to the gelatine a satisfactory join could be made without further treatment. In practice tliis is not the case. Flexible Joints The material used for attaching one ' film to another must be as flexible as the base itself, othernTse we should have trouble with the film passmg through the projector, and it has been found that the most satisfactory method of joining two films Ls to use a substance which in spite of its name is not really a cetnent but a solvent of the celluloid base itself. This substance does not affect the gelatine and therefore it cannot be used to bring about adhesion between the celluloid and the gelatine surface, so we must remove the gelatine surface bj' scraping and in this way expose the plain film l>eneath. ^^Tlen this is done the solvent is applied to the two faces of the film which have to be brought into contact and pressure exerted. Immediately the solvent softens and renders stickjthe two sm-faces in contact with one another and the pressure causes the two to be brought into perfect contact a genuine weld or homogeneous joint thus being made. A proi>erly formed splice thus becomes even .stronger than the original film and it is im.possible to break it awa\without fracturing the film surface itself. So niuch, then, for the principle of splicing. Let us see how it is carried out meehanicallj-. For the purpose of our explanation we must assiune the film has broken in a jagged fashion and we desire to join the two broken ends. The fii\st thing to do then is to trim them straight, which can be done with a pair of scissors if desired. We must next so arrange the two ends that scrape off the gelatine siu-face to the extent of the overlap. The simplest v.ay to do this is to moisten it, when it will be found that the gelatine will scrape off very easily, leaving the bare film. Havnng made siu-o that the film is quit* dry we then quickly dip a brush into the solvent and wipe it along the bared portion, immediateh' brintring the other end of the film over the scraped end and pressing the two into firm contact with the fingers. In order that the correct distance shall be maintained the two last sprocket holes on one side and the two first on the other should be placed o\er the piece of the gauffe when the joint is made and in this way the correct distance will be preserved. The joint takes but twenty to thirty seconds to set firmly anil in about another half-minute can be passed [Photo: Central Press Three Royal Film Makers. The Prince of Wales, the Duke of York and the Duke of Gloucester are all keen cinephotographers there is only just sufficient overlap to make a satisfactorj" joint and we must also see that the correct distance is maintained between adjacent perforated holes, otherwise the film will not pass over the feed and take-up sprockets of the projector. In order to maintain this difference we need some kind of gauge, the simplest form of which consists of a piece of metal ■with projecting pins corresponding in position \vith the exact difference between the adjacent sprocket holes. Guide Pins If then the end of one side of the film is placed over one pair of pins and the other end over the second pair, we can judge how much to cut the film so as to n^ake the correct overlay. Having done this and marked the amount of overlap we must next through the projector with safety. All this soimds tedious and difficult but the work is made extremely easy with the simple gauges and guides pro\'ided by all of the camera and projector manufacturers. Such outfits as the Kodak and the Ensign cost but a few shilh'ags and consist of a bottle of cement or solvent, pieces of metal with projecting pins to maintain the correct distance, gauges to show just where to cut the film and allowing just the correct amount to project so that the scraped surface will correspond with the overlap of the other film, and full instructions. Some of the more expensive splicers such as the Craig and the Griswold as well as the Kodak Automatic Splicer, cost two or three pounds, but are so cleverly made that spUcing is niade child's play, and as time-savers thej' are a good investment. II