We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.
Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.
II
cause excessive tension or slackness of the film during its passage through the processing machine. From this standpoint the new safety film shows up quite well, since it will be seen from Fig. 5, that during the first ten minutes of drying after 30 minutes' soaking the new safety film shrinks 0.14% as against 0.07% for nitrate, while the old safety shrinks 0.31%.
Rate of Shrinkage of Film Base at 70° C— Under an accelerated aging test for permanent shrinkage at 70° C, the results of which are depicted in Fig. 6, the new safety material displays marked superiority over nitrate film, and is vastly superior to the old safety film. In this respect, indeed, the new film shows a valuable improvement which may have many repercussions on the design of motion picture equipment from the aspect of sprocket specifications.
Rate of Shrinkage of Motion Picture Positive Film at 70° F.— Permanent shrinkage tests conducted at normal temperature over a period of 15 months fully substantiate the results obtained under accelerated aging (Fig. 7).
I II. PRACTICAL TESTS
Following on these measurements of characteristics, which are of more particular interest to the manufacturer than the user, a series of practical tests was conducted in the U.S.A., in which the safety films were compared directly with nitrate film.
Laboratory Measurements
First the behaviour of the films as regards swell and shrink during processing was measured, together with the curl characteristics. It will be
8 12
TIME. MONTHS
fig. 6. Rate of shrinkage (lengthwise) of motion picture positive film base at 71° C. (160° F.).
Fig. 7. Rate of shrinkage (lengthwise) of motion picture positive films. Individual developed strips were stored, freely exposed to circulating air and shrinkage values calculated from the initial dimensions of the raw stock.
seen from Table II that the degree of curl encountered at any stage was very small, and can be ignored for all practical purposes. As regards swell and shrinkage, the new safety film acquires an increase in length of 0.28% on leaving the fixing solution, as against 0.14% for nitrate and 0.42% for the old safety. Final shrinkage or stretch immediately after processing is observed to be — 0.02% for the new safety, — 0.06% for the nitrate, and -j-0.02% for the old safety — all perfectly satisfactory values. On tests at commercial processing laboratories, no troubles have been reported in handling the new film.
Next the wearing properties of the film on projection were found in a preliminary manner by projecting short lengths of film over and over until breakdown. On this test, the results of which are set out in Table IV, nitrate film displayed slightly superior wearing qualities, as was to be expected from a study of the mechanical properties of the various film bases.
Following this, films were projected in the normal wa}^ and studied for