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.
1948 SAFETY FILM SUPPORT 341
TABLE III
PROCESSING OF HIGH-ACETYL 5302 (35-Mai) FILM Tests in Commercial Laboratories
Machine
Film
Threading
Approximate Curl at
Length,
Drying
Feet of
Rewind,
Laboratory
Feet
Conditions
Test
Inch
Difficulties
A
1750
77 °F.— 42% R.H.
21,000
+0.09
None
B
2120
63 °F.— 60% R.H.
12,000
+0.14
None
determined by experimental projection under conditions of actual use. Preliminary tests of a laboratory nature were made in this investigation, and were followed by trade tests involving prints of several commercial feature pictures issued through selected film exchanges in different parts of this country.
Preliminary laboratory tests for physical behavior of the film involved continuous projection of short lengths of film for increasing lengths of time, followed by examination of the film for perforation damage and general appearance. A summary of the results is given in Table IV. It will be noted that slight perforation damage began to take place after about 200 projections for both the high-acetyl and the nitrate films, as compared with 100 projections for the acetatepropionate safety film. This became progressively more severe on all products until failure by complete perforation breakdown at 520 runs for the high-acetyl film as compared with 380 runs for the acetatepropionate safety and 644 for the nitrate. It should be emphasized that the numerical values of runs before failure are of significance only for comparative purposes, and do not necessarily indicate the number of runs to be expected in trade use.
Another type of laboratory test involved projection of rolls of the three types of film on a Simplex E-7 projector, with a projection throw of 157 feet to a screen 30 feet by 40 feet. Initial tests with nonrotating positive high-intensity arcs up to 65 amperes in mirror optical system lamps resulted in entirely satisfactory performance of all three types of film. A more severe test was then undertaken, using a rotating positive high-intensity arc (13.6-mm positive carbon) at 175 amperes in a condenser optical system lamp and employing an Aklo No. 3966 heat-absorbing glass filter. Certain characteristic differences in the films became evident in this test, as recorded in Table V. The acetate propionate safety 5302 film here showed