1、SMPTE RECOMMENDED PRACTICE RP 70-2002 Revision of RP 70-1997 Seecificatisras fsr Flutter Test Film for 16-mm Audio Reproducers, Photographic Type Page 1 of 2 pages 1 scope This practice specifies a test film for determining the presence of flutter in 16-mm motion-picture photographic audio reproduce
2、rs operating at 36 ft (11 m) per minute. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this practice. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties
3、to agreements based on this practice are encouraged to investigate the possibility of applying the most recent edition of the standards indicated below. AES 6-1982, Method for Measurement of Weighted Peak Flutter of Sound Recording and Reproducing Equipment ANSVNAPM IT2.19-1994, Photography - Densit
4、y Measurements - Part 2: Geometric Conditions for Trans- mission Density ANSVSMPTE 109-1998, Motion-Picture Film (16-mm) - Perforated 1 R and 2R SMPTE 41-1999, Motion-Picture Film (16-mm) - Prints - Photographic Audio Records SMPTE 223M-2001, Motion-Picture Film - Safety Film 3 Test film signal 3.1
5、Frequency The audio record shall reproduce at a frequency of 3150 Hz I25 Hz when the linear velocity of the film is 24 perforations per second or approximately 36 ft per minute (7.2 in or 18.3 cm per second). 3.2 Distortion The total harmonic distortion of the recorded signals shall not exceed 0.5%.
6、 3.3 Location and dimensions The location and dimensions of the recorded audio record shall be in accordance with SMPTE 41. Copyright O 2002 by THE SOCIETY OF MOTION PICTURE AND TELEVISION ENGINEERS 595 W. Hartsdale Ave., White Plains, NY 10607 Approved July 26,2002 (914)761-1100 RP 70-2002 3.4 Reco
7、rding The test film shall have an originally-recorded, variable-area audio track. The geometrical modulation of this recording shall be 80% f 5% of the maximum nominal geometrical amplitude of 0.055 in (T.40 mm). This is equivalent to an rms nominal geometrical amplitude of 0.0440 in f 0.0028 in (1
8、.118 mm f 0.071 mm). 3.5 Signal fluctuation The output level of the film shall be constant within k 0.25 dB. This is equivalent to a peak-to-peak amplitude tolerance of approximately 2.9% of the 80% modulation or f 0.0013 in (0.033 mm). 3.6 Density The density of the dark portion of the audio track
9、shall be between 1.2 and 1.4 and shall be uniform throughout the length of the film within a tolerance of f 0.05. The combined base and fog density shall be 0.05 f 0.01. All densities shall be measured in conformity with ANSI IT2.19. 3.7 Flutter The weighted peak flutter of the audio record shall no
10、t exceed f 0.10% when measured in accordance with AES 6. 3.8 Azimuth The azimuth of the audio record shall be 90“ f 3 to the reference edge of the film. 4 Filmstock 4.1 The film stock, preferably polyester, shall be splice-free, of the low-shrinkage, safety type in compliance with SMPTE 223M, and cu
11、t and perforated in accordance with long-pitch dimensions specified in ANSVSMPTE 109. 4.2 In the event that triacetate film stock is used, it shall be splice-free and shall have a maximum lengthwise shrinkage of 0.50% when tested as follows: At least 20 strips of film approximately 31 inches in leng
12、th shall be cut for measurement of shrinkage. After normal development and drying (not over 80F 27“C), the strips shall be placed at least 1/4 in apart in racks and kept for seven days in an oven maintained at 12OOF (49C) and a relative humidity of 20%. The strips shall then be removed, reconditione
13、d thoroughly to 50% relative humidity at 70F (21 OC), and the shrinkage measured by a suitable method. 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 ANSVSMPTE 109. 5 Identification
14、Each test film shall be identified by a suitable identification marking. This marking shall be printed lengthwise in the picture area and the spacing between consecutive titles shall be approximately 12 in (305 cm). NOTE - Test films made in accordance with this practice are available from the Society of Motion Picture and Television Engineers. Page 2 of 2 pages
