Home Movies and Home Talkies (Jun 1933-May 1934)

HOME MOVIES & HOME TALKIES 173 Fig. 3. End of film scraped for cementing fovuitl to this pi'oblem antl so we must remove the gelatine coating for just the distance of the overlap so that two pieces of bare celluloid can be brought together. There are two ways of removing this gelatine coating, one being to moisten it, which softens it, and then scrape it off, and the other being, so to speak, to grind it off with a dry scraper. There are advantages in both ways, but the dry scraping is becoming more and more popular, largely because it is less messy and because the scraping can be done accurately for just the distance required. While this can be done with the moistening method there is a tendency for the moisture to spread into that portion of the picture which we do not desire to scrape, unless the work is very carefully carried out. Cements Once the gelatine coating has been removed we ajiply a special liquid by means of a, brush and press the two portions together, maintaining the correct distance between the sviccessive frames by registering pins in the splicing ajDparatus. This special liquid is called film cement, but this is scarcely a good word although generally adopted. Really, it is a film solvent causing both pieces of celluloid to dissolve on their surfaces and when pressure is applied the two parts become welded together as one. The two parts of the film, therefore, are not stuck together with a cement like gum or glue, but are actually welded into one another. This is why a well-made splice is as strong or stronger than the film itself. Film cements vary a good deal in their composition but most of them have a characteristic smell. Their consistency is generally that of thin gum antl they are either colourless or very pale yellow; in one or two cases the cement is water white and of the consistency of water, smelling like very strong vinegar. This is because it consists largely of a substance known as glacial acetic acid, which very readily dissolves the celluloid surface. How To Choose Each of the leading film makers sells his own cement ; thus you can get Kodak cement for Kodak films, Agfa for Agfa films and Selo for Selo films. Johnson's of Hendon, the wellknown chemical firm, also sell safety film cement which I have found work excellently with all makes, but it does not follow that one maker's cement works well with another maker's film and there is frequently trouble through a lack of luiderstanding on this point. For example, I have found nothing better for Kodak film than Kodak cement, but it is rarely possible to make as good a splice with Selo film using Kodak cement owing to the different composition of the base. Some cements, however, seem to work well with all films. Pathe film seems to require a cement having a high percentage of glacial acetic acid and as the Pathe's own cement is so made I generally recommend it in such cases. Johnson's cement, however, works just as well with Pathe film as with the other makes. So far you will notice I have not dealt with the actual procedure in splicing a film for the .simple reason that you cannot make a splice without a splicing outfit, and simple and perfectly clear instructions on the actual making of a splice are given with each of them. The points I am dealing with, however, are rarely mentioned, and for this reason I feel they will be more heljaful than merely quoting standard directions given with most film splicers. Speed Necessary ! One thing is essential in all makes of film and all methods of splicing. You mtist bring the two p>ieces of film together immediately after you have applied the cement ! This is essential. Some cements, such as the Kodak, dry extremely rapidly by evaporation and unless the two parts are brought together at once you will not get a proper splice or, in fact, any .splice at all ! This rapid drying is often a great advantage, for once the two parts have been brought together and put under pressure ten or fifteen seconds is quite sufficient for the time of contact, and in less than half a minute the film can be taken out and put in the projector. Some cements, notably those of the water consistency with a large proportion of glacial acetic acid, are not so rapid in their action and the splice should be left for a little longer time before u.se. Only just sufficient cement should be used to make a thin layer on the celluloid base. Too much cement will '■ squelch " otit and make a mess on the rest of the film and will certainly not make the splice any stronger. Too little will mean that all the film that should be in contact will not be touching and the splice will soon break open. A Finishing Tip Most splicing arrangements have a ]3resstu-e plate that you must lift before yoti can remove the film. When you lift this there will usually be a little cement still showing, and this should be removed immediately with a piece of cloth and a quick wipe. Lift the film carefully from off the registering pins and squeeze the two ends together between your finger and thtimb for a few seconds. Yoti should then have a perfectly .satisfactory join. Another ])oint which is often overlooked is that you must have the right ends joined ! It is by no means easy, particularly when you are beginning editing, to distinguish which way up a picture is and far too often you will find after you have made a good splice that the picture is upside down immediately following your join ! Cx)ntretemps of this nature can be avoided by making a rule always to have the top of the pictiu-e pointing to the left when you are working. ( I'o be contitfte-i] Fig. U. Completed splice, showing overlap at sprocket holes