The Cine Technician (1938-1939)

150 T HE CI X E TECHNICIA N Jan. Feb., 1980 THREE NEW NEGATIVE FILMS by I. D. WRATTEN. Technical Service, Kodak Ltd. THE characteristics most essential tor negative films to be used for motion picture purposes are not onlj those ol high speed and fine grain, hut also include exposure latitude and imijormit\ ol product. All these requirements have been met in the production of the new films, which have been named Kastman Plus X, Eastman Super XX, and Eastman background X. EASTMAN PLUS X Eastman Plus X, code number 1231, is a new motion picture negative material for studio use. It is considerably faster than Eastman Super X. and has even finer gram, a combination which has previously been considered unobtainable. This new film with its higher speed and excellent exposure latitude will assist in reducing studio lighting problems, and is in every way a worthy successor to Eastman Super X. EASTMAN SUPER XX Eastman Super XX, code number 1232, is an extremely high speed negative material suitable for use under unfavourable lighting conditions. Actual night exteriors may be undertaken witli confidence using this film. While its speed is considerably in excess of that obtained in Plus X, graininess has been kept at a satisfactorily low level. EASTMAN BACKGROUND X This material, code number 1230, is designed specially for negatives from which positives are to be made for background projection, ami represents a considerable advance in both fineness of grain and speed when compared with Eastman Background Panchromatic, code number 1213, which it will replace. mm mmwr" SPECTRAL SENSITIVITY In spectral sensitivity, Eastman Plus X, Eastman Super X.\, and Background X belong to the Eastman B classification, whereas Eastman Super X belongs to the C class. Tney have extremely high colour sensitiveness, corresponding approximately to tne colour sensitiveness of the eye, and Having somewhat greater green sensitivity than Super X. Wedge Bpectographs, snewn in Figure I, illustrate the difference m spectral scnsitivitx existing between the three new films and Eastman Super X. FILTER FACTORS Filter factors to daylight for l'lus X, Super XX, and Background X, are given in tabulated form in Figure 2. Filter Factors. Eastman Super XX Filter Eastman Plus X Background Aero 1 1.25 1.25 Aero 2 1.5 1.5 3-X-5 4 4 5-X-5 5 5 Q 3 3 23A 4 4 X!). 0.25 1.8 1.8 XI). 0.50 3.1 3.1 Eigurc i Figure 2. DEVELOPMENT CHARACTERISTICS The Time-gamma characteristics of the three new films are shown in Figure 3. It will be seen that the differences in development time to produce the recommended gamma value of 0.(55 are expressed in terms of the percentage increase or decrease in time as compared with a well-known product, i.e., Eastman Super X. This is done in preference to quoting actual times, since while the differences in rates of development are reasonably consistent under widely differing machine and developer conditions, the actual times of development required for, say, Eastman Super X, vary considerably from laboratory to laboratory. As will be seen by an examination of the curves, Eastman Plus X lias very nearly the same rate of development as P^astman Super X, while Eastman Super XX requires approximately 50 per cent, longer development to attain a gamma value of 0.65. Eastman Background X requires about 20 per cent, less time than Eastman Super X to achieve the same gamma value. SPEED It is always difficult to reconcile speed numbers with the practical differences existing between picture negative products, but as an example of the relative speeds of these new products it may be stated that under average studio lighting conditions Eastman Plus X requires approxmately one half, and Super XX only one quarter the amount of light normally employed where Eastman Super X is used, assuming that all three films are developed to similar gamma values.