1、BRITISH STANDARD BS ISO 8395:1995 Implementation of ISO8395:1995 Cinematography Test films for the reproduction of70mm motion-picture release prints with magnetic stripes Specifications ICS 37.060.20BSISO8395:1995 This BritishStandard, having been prepared under the directionof the Consumer Products
2、 and Services SectorBoard, was published underthe authority of the Standards Board and comes into effect on 15October1995 BSI 02-2000 The following BSI references relate to the work on this standard: Committee reference CPM/5 Draft for comment94/303019DC ISBN 0 580 24800 3 Committees responsible for
3、 this BritishStandard The preparation of this BritishStandard was entrusted by Technical Committee CPM/5, Audio Technology, upon which the following bodies were represented: Association of Independent Cinemas British Broadcasting Corporation British Film and Television Producers Association British
4、Film Institute British Kinematograph, Sound and Television Society Broadcasting Entertainment Cinematograph and Theatre Union Cinema Exhibitors Association ITV Association (ITVA) Institute of Amateur Cinematographers Royal Photographic Society Amendments issued since publication Amd. No. Date Commen
5、tsBSISO8395:1995 BSI 02-2000 i Contents Page Committees responsible Inside front cover National foreword ii Foreword iii Text of ISO8395 1BSISO8395:1995 ii BSI 02-2000 National foreword This BritishStandard reproduces verbatim ISO8395:1995 and implements it as the UK national standard. This BritishS
6、tandard is published under the direction of the Consumer Products and Services Sector Board whose Technical Committee CPM/5 has the responsibility to: aid enquirers to understand the text; present to the responsible international committee any enquiries on interpretation, or proposals for change, an
7、d keep UK interests informed; monitor related international and European developments and promulgate them in the UK. NOTEInternational and European Standards, as well as overseas standards, are available from Customer Services, BSI,389 Chiswick High Road, London W44AL. A British Standard does not pu
8、rport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front
9、 cover, pagesi andii, theISO title page, pagesii toiv, pages1 to4, an inside back cover and abackcover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.ISO8395:1995(E) ii BSI 02-2000
10、 Contents Page Foreword iii 1 Scope 1 2 Normative references 1 3 Types of test film 1 4 Specifications 2 Annex A (informative) Behavioural characteristics of film base Inside back cover Annex B (informative) Bibliography Inside back cover Table 1 Characteristics of test signal for checking and adjus
11、ting azimuth 2 Table 2 Characteristics of test signal for checking and adjusting reference flux electrical output 2 Table 3 Characteristics of test signal for checking and adjusting frequency response 3 Table 4 Calculated relative levels in decibels against frequency 3 Table 5 Characteristics of tes
12、t signals for measuring non-uniformity in velocity of film travel (flutter) 4 Descriptors: Cinematography, sound recording, magnetic recording, sound reproduction, recording tracks, motion-picture film, motion-picture film70mm, reference sample, specifications.ISO8395:1995(E) BSI 02-2000 iii Forewor
13、d ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technica
14、l committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of ele
15、ctrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least75% of the member bodies casting a vote. International Standard ISO8395 was prepared
16、by Technical Committee ISO/TC36, Cinematography. Annex A and Annex B of this International Standard are for information only.iv blankISO8395:1995(E) BSI 02-2000 1 1 Scope This InternationalStandard specifies basic technical characteristics for magnetic sound test films used for checking, adjusting a
17、nd measuring70mm motion-picture projector sound systems and sound reproduction channels of motion-picture installations. This International Standard includes specifications for test films intended for checking, adjusting and measuring of: a) azimuth of the magnetic head gaps (azimuth alignment test
18、film; see Table 1); b) output level balance of several motion-picture projectors or systems and interchannel balance on each projector or system (signal level test film; see Table 2); c) frequency response of the sound reproduction channels (multi-frequency test film; see Table 3 and Table 4); d) no
19、n-uniformity in velocity of film travel (flutter) (flutter test film; see Table 5). 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were v
20、alid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International
21、Standards. ISO266:, Acoustics Preferred frequencies 1) . ISO2404:1986, Cinematography Six-track magnetic sound records on70mm striped release prints Locations and dimensions. ISO3023:1995, Cinematography65mm and70mm unexposed motion-picture film Cutting and perforating dimensions. ISO8590:1994, Cine
22、matography Audio records on70mm motion-picture release prints with magnetic stripes Recorded characteristic. ANSI S4.6:1982, Recorded flux of magnetic sound records at medium wavelengths, methods of measuring. ANSI/IEEE152:1992, Audio Program Level Measurement. CCIR Report79-2:1994, Measurement of t
23、he characteristics of sound signals recorded on magnetic tape. DIN45520:1973, Magnetic tape recorders; measurement of the absolute level of the magnetic flux and its frequency response on magnetic tapes. EBU Technical Document3205-E:1979, The EBU standard peak-programme meter for the control of inte
24、rnational transmissions. IEC386:1972, Method of measurement of speed fluctuations in sound recording and reproducing equipment. 3 Types of test film It is recognized that two different types of magnetic test film are used for the evaluation and adjustment of magnetic film reproducers. These test fil
25、ms differ in the way their magnetic flux levels are measured, and in the detailed procedures of their application in system evaluation and adjustment. In this International Standard, both types of magnetic test film are specified, according to the following definitions. a) Type185 Magnetic flux leve
26、ls are measured using the procedures specified in ANSI S4.6 and CCIR79-2. The reference short-circuit flux level shall be185nWb/m. The test film signal output level shall be6dB below the reference flux level. These test films were developed for use generally in countries with a mains frequency of60H
27、z, and for measurement with VU meters conforming to ANSI/IEEE152. NOTE 1The method for measuring magnetic flux level given in ANSI S4.6 uses a special reproducing head with two symmetrical gaps. The magnetic film to be measured is run in contact with the front gap and then in contact with the rear g
28、ap. The flux is calculated from the two EMF values and the head data. b) Type320 Magnetic flux levels are measured using the procedures specified in DIN45520. The reference short-circuit flux level shall be320nWb/m. The test film signal output level shall be10dB below the reference flux level. These
29、 test films were developed for use generally in countries with a mains frequency of50Hz, and for measurement with SPP meters conforming to EBU Technical Document3205-E. NOTE 2The method for measuring magnetic flux level given in DIN45520 uses a search coil to sense the flux of a very long wavelength
30、 recording. The recording head is then fed with the same current, but at the reference frequency to produce a recording for calibrating a high-efficiency reproducing head. 1) To be published. (Revision of ISO266:1975)ISO8395:1995(E) 2 BSI 02-2000 The calibration of a magnetic film reproducer resulti
31、ng from the use of a Type320 magnetic test film will differ from that obtained from the use of a Type185 magnetic test film, and will generally give a result about1dB higher for identical flux levels. 4 Specifications 4.1 Test films shall be made on motion-picture film, the cutting and perforating d
32、imensions of which are in accordance with ISO3023. (See also Annex A). 4.2 Location and width dimensions of sound records shall be in accordance with ISO2404. 4.3 Magnetic recording characteristics for multifrequency test film shall be in accordance with ISO8590. 4.4 Test films shall be splice-free,
33、 except where joins are an essential part of the test film. 4.5 70mm test films shall be recorded at a film velocity equivalent to24 frames(120 perforations) per second nominally570mm(22,4in) per second. All frequency and velocity tolerances shall relate to this stated velocity. 4.6 Each test film s
34、hall be provided with written identification on the outside of the container, including the following information: type of test film (Type185 or Type320), function of the film, base material (triacetate or polyester), date and place of recording, and a statement that the test film conforms to this I
35、nternational Standard. 4.7 Within multifrequency test films, each frequency shall be identified by voice announcements preceding that frequency segment. The peak level of voice announcements shall not exceed the peak level of modulation. 4.8 If multi-track test films are made on a fully magnetic coa
36、ted motion-picture film, the individual records shall be made in accordance with this International Standard, including the specific International Standards referenced in clause2. Table 1 Characteristics of test signal for checking and adjustingazimuth (azimuth alignment test film) Table 2 Character
37、istics of test signal for checking and adjusting reference flux electrical output (signal level test film) Characteristic Value Signal frequency Frequency tolerance Azimuth tolerance for each track Type185 signal output level Type320 signal output level Output uniformity Minimum duration of signal 1
38、6kHz 3% 3 6dB below reference flux level 10dB below reference flux level 0,5dB 100s Characteristic Value Signal frequency Frequency tolerance Type185 reference short-circuit flux Type320 reference short-circuit flux Reference flux tolerance Output uniformity Harmonic distortion, total Flutter, IEC w
39、eighted Minimum duration of signal 1000Hz 3% 185nWb/m 320nWb/m 10nWb/m 0,5dB 2% 0,1% 60s NOTEBecause of the differences in calibration procedures, Type185 reference flux is actually only about3,8dB below Type320 reference flux (see clause3, notes1 and2).ISO8395:1995(E) BSI 02-2000 3 Table 3 Characte
40、ristics of test signal for checking and adjusting frequency response (multi-frequency test film) Table 4 Calculated relative levels in decibels against frequency (see4.12.1) Characteristic Value Reference signal frequency Type185 signal output level at reference frequency Type320 signal output level
41、 at reference frequency Short-circuit flux tolerance at all frequencies Output uniformity at all frequencies Output deviation within each frequency Time constant characteristics Frequency tolerance at all frequencies Minimum duration of signal at reference frequency Minimum duration of signal at all
42、 other frequencies 1000Hz 6dB below185nWb/m 10dB below320nWb/m 0,5dB 0,5dB 0,3dB 31804s and354s (3%+2Hz) 20s 8s Frequency series in order of their location in the test film Short-circuit flux aRelative level bHz nWb/m dB Type185 Type320 1000 c20 d 25 d 31,5 40 50 63 80 125 160 d 250 315 400 500 1000
43、 c 2000 3150 6300 8000 10000 12500 16000 92,7 255,5 212,2 178,0 151,9 134,1 121,1 111,8 102,1 99,3 96,6 95,8 95,2 94,7 92,7 86,8 78,0 55,5 46,9 39,2 32,4 25,9 101,2 278,9 231,6 194,3 165,7 146,4 132,1 122,0 111,4 108,4 105,4 104,5 103,9 103,4 101,2 94,8 85,1 60,6 51,1 42,8 35,4 28,3 0 8,80 7,19 5,66
44、 4,29 3,21 2,32 1,63 0,84 0,59 0,35 0,28 0,23 0,19 0 0,57 1,51 4,46 5,93 7,47 9,13 11,07 a See notes1 and2 in clause3. b Calculation based on a normalizing constant of0,1942443. c Reference frequency and normalization point for the response curve. d Optional frequency.ISO8395:1995(E) 4 BSI 02-2000 T
45、able 5 Characteristics of test signals for measuring non-uniformity in velocity of film travel (flutter) (flutter test film) 4.9 Test films recorded to a wider track width than the reproducing head will cause the head to gather fringe effect flux at long wavelengths. A correction shall, therefore, b
46、e applied to simulate the normal effect on the head of a standard width track. The values and application of such corrections shall be clearly stated on a correction sheet accompanying each individual test film. 4.10 This International Standard specifies the minimum test signals for magnetic sound t
47、est films. Additional test signals may be added if desired. If such test signals are added, they shall be identified (see4.6 and4.7). 4.11 The test signals for measurement and adjustment of azimuth, reference level, and frequency response may be presented as individual test films, or two or more fun
48、ctions may be grouped within a single test film. A flutter test film shall be a separate film. 4.12 Frequency response is defined for all possible frequencies within the appropriate bandwidth by the specification of time constants to define the response curve. 4.12.1 The relative levels for multifre
49、quency films (see Table 4) are representative points along the locus defined by the time-constants,354s and31804s, given in Table 3 (defined in ISO8590). The test film levels (after application of incremental corrections supplied when necessary with each individual test film) shall agree within the tolerances defined in this International Standard. NOTE 3This International Standard calls for31804s low-frequency equalization. Equalization with no low-frequency record boost (a low-frequency time const
