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April, 1946
AMERICAN STANDARDS ON MOTION PICTURES
297
American Standard Specifications for
400-Cycle Signal Level Test Film
for 16-Millimeter Sound Motion Picture Projection Equipment
K-A'. V . S. Pal. Off.
Z22.45-1946
1. Scope and Purpose
1.1 This specification describes a 400-cycle signal level test film for use in testing 16-mm sound motion picture projection equipment.
2. Test Film
2.1 Recording. The test film shall have an originally recorded direct playback positive variable-area sound track recorded at an amplitude of 0.048 =fc 0.0015 inch. The frequency of the recording shall be within ± 8 cycles of nominal frequency.
The density of the dark portion of the sound track shall be between 1.7 and 2.0. The density throughout the length of the film shall be as uniform as is consistent with the state of the art.
The combined base and fog density, measured as visual diffuse density, shall be 0.05 ± 0.01 when measured on an integrating sphere densitometer or a polarization densi to meter.
The wave form distortion of the recording shall not exceed 5 percent.
2.2 Film Stock. The film stock used for the test film shall be cut and perforated in accordance with the Amer^an Standard 16Mm Sound Motion Picture Film; Cutting and Perforating for Negative and Positive Raw Stock, Z22.12-1941, or latest revision thereof.
2.2.1 Res/stance to Shrinkage. The film stock used for the test film shall have a maximum lengthwise shrinkage of 0.50 percent when tested as follows: At least 20 strips of film approximately 31 inches in length shall be cut for measurement of shrinkage.
After normal development and drying (not over +80F [+26.7C]), the strips shall be placed at least !4 inch apart in racks and kept for seven days in an oven maintained at -f 1 20 F ( -j 49 C) and a relative humidity of 20 percent. The strips shall then be removed, reconditioned thoroughly to 50 percent relative humidity at +70F (+21.1 C), and the shrinkage measured by an adaptation of the pin-gage method outlined in Research Paper RP-1051 of the National Bureau of Standards. The percent shrinkage shall then be calculated on the basis of deviation from the nominal dimension for the length of 100 consecutive perforation intervals given in American Standard Z22.12-1941, or latest revision thereof.
2.3 Standard Length. The standard length of the 400-cycle signal level test film shall be 100 feet.
2.4 Measurement Requirements. Each film shall be measured for amplitude of the modulation, for image density, and for combined base and fog density. The measurements shall be made at a point approximately mid-length of the film and at points between 5 and 10 feet from each end. The results of the measurements shall be stated on a card furnished with each test film.
2.5 Leader and Trailer. Each test film shall be provided with a suitable leader, title, and trailer.
NOTE: A test film in accordance with this standard is available from the Society of Motion Picture Engineers.