The Cine Technician (1938-1939)

40 T H E C 1 N K T EC II M (J I A N July-August. 1938 DUPLICATE NEGATIVES IN MOTION PICTURE PRODUCTION by MA^sY more duplicate negatives are being used in film production than heretofore. This is mainly due to the larger number of optical effects and library shots which go to make up a full length picture. In addition, complete dupe. negs. are made from many full length features and shorts, and used by foreign countries to print off their own release copies. Because of this demand many duplicating emulsions are being placed on the market to cope with this specialised work. It is not my object to comment on the various qualifications of the different manufacturers' duplicating emulsions. It is sufficient to state that great advancement has been made during the past few years in the manufacture of these. Consequently, there seems little chance of further outstanding improvement until such time as the intermediate process of making a master positive has been eliminated. This would mean that duplicate negatives could be produced direct from originals by reversal, with a definite gain in quality and a reduction in the margin of error due to the intermediate process. Experiments have already been conducted along these lines in still photography, but the speed of the emulsion used is much too slow at the moment to make it practical for motion picture work. Graininess and its Relation to Duplicate Negatives On the following factors depend the graininess of the duplicate negative : — 1. — The amount of grain present in the original negative. 2. — The quality of the duplicating emulsions used. 3. — The composition of the developer. 4. — The time of development. Present-day original negatives are very free from grain, except in the case of scenes with a large area of deium density, and lacking in detail, such as sky and misty scenes. OUT OF LEO'S DEN (Continued from previous page) top rank star, or director, are sometimes very useful standbys and money makers — as long as they have good stories. It may easily happen that an "A" picture with one or more stars may turn out not so good. With its average £200.000 budget, this is liable to cause a serious loss. So Darvll Zanuck, one; of the cleverest "business producers" evolved the "series" pictures — now being copied by other studios. These pictures usually concern a family or character— the "Jones Family," "Charlie Chan," etc., and may cost as little as £50,000, though they usually run at about £80,000! It will be seen that there is an economy in sets. The sets comprising the family's house are left standing permanently and not even re-vamping is necessary. With these words, I must beg to excuse myself, as I seem to be in danger of falling between two lions! I hope I have not seemed too enthusiastic about Hollywood. Boiling it all down, I suppose the real reason for Hollywood's superiority is the enormous amount of money in circulation. But then, since 00 per cent of the world's gold is buried in the hills of Kentucky, what are we to do? Graniness is caused by the siiver halides in the emulsion layer clumping together as they turn into metallic silver during development, it is these grain dumps which we see on the screen. The faster the speed of an emulsion, the more silver is used in its composition, and the thicker the emulsion layer, consequently the coarser the grain. The thinner the emulsion layer, the finer the grain, and the better the resolving power (ability to render fine detail), since the light does not have to penetrate so far and therefore is prevented from "spreading" due to the semi-opacity of the emulsion itself. Because of the special advantages of slow emulsions, the loss of speed, provided it is within reason is no serious drawback in duplicate negative processing. The type of developer used also plays an important part in the quality and amount of grain in the duplicate negative. There are numerous fine grain developing formulae available, but practical experience has proved that metol-hydroquinone-borax developers similar to the Kodak D76 are best, in that they do not lower the effective emulsion speed. Time of development also governs the size of the grain clumps. We all know that as development increases, so also does the contrast of the developed image. This is because those parts of the emulsion which have received sufficient exposure continue developing, whilst those that haven't will go so far and no further; consequently, the degree of density between the highlights and shadows increases with development. Now in order that density may increase, the silver grains clump together more and