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1、BRITISH STANDARD BS ISO 12606:1997 Cinematography Care and preservation of magnetic audio recordings for motion-pictures and television ICS 33.160.30; 37.060.20 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 12:01:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 12606:1997 This British S
2、tandard, having been prepared under the direction of the Consumer Products and Services Sector Board, was published under the authority of the Standards Board and comes into effect on 15 September 1997 BSI 09-1999 ISBN 0 580 28445 X National foreword This British Standard reproduces verbatim ISO 126
3、06:1997 and implements it as the UK national standard. The UK participation in its preparation was entrusted to Technical Committee CPW/36, Cinematography, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries
4、 on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British
5、Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British St
6、andard does not purport 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 cove
7、r, an inside front cover, pages i and ii, the ISO title page, pages ii to iv, pages 1 to 9 and a back cover. 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. Amendments issued since
8、publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 12:01:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 12606:1997 BSI 09-1999i Contents Page National forewordInside front cover Forewordiii Text of ISO 126061 Licensed Copy: sheffieldun sheffieldun, na, Sun
9、Nov 26 12:01:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 12:01:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 12:01:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 12606:1997
10、ii BSI 09-1999 Contents Page Forewordiii 1Scope1 2Normative reference1 3Storage hazards and concerns1 4Summation of storage recommendations1 5Derivation of recommended storage conditions2 6Chemical stability2 7Magnetic corruption3 8Physical distortion3 9Preparation of media for storage4 10Removal of
11、 media from low-temperature storage4 11Preparation for reproduction after storage4 12Preservation of deteriorating recordings5 Annex A (informative) Additional data6 Annex B (informative) Bibliography7 Figure A.1 Cross-section of magnetic recording media (schematic)6 Table 1 Storage conditions1 Tabl
12、e A.1 Diversity of analog audio magnetic records7 Descriptors: Cinematography, motion-picture film, audio data, sound recording, magnetic recording, storage, preservation, stabilization. Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 12:01:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO
13、 12606:1997 BSI 09-1999iii Foreword 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
14、 in a subject for which a technical 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 Comm
15、ission (IEC) on all matters of electrotechnical 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 least 75 % of the member bodies casting a vote. Internat
16、ional Standard ISO 12606 was prepared by Technical Committee ISO/TC 36, Cinematography. Annex A and Annex B of this International Standard are for information only. Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 12:01:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iv blank Licensed Copy: shef
17、fieldun sheffieldun, na, Sun Nov 26 12:01:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 12606:1997 BSI 09-19991 1 Scope This International Standard recommends storage conditions for stabilization and preservation of magnetic audio recordings for motion-picture and television production. It re
18、commends the desirable storage conditions for magnetic audio recordings, as they may remain in library or vault storage between periods of intermittent reproduction or duplication. It describes the care and handling of magnetic media intended to be introduced into, or removed from, storage. 2 Normat
19、ive reference The following standard contains provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the edition indicated was valid. All standards are subject to revision and parties to agreements based on this Internation
20、al Standard are encouraged to investigate the possibility of applying the most recent edition of the standard indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ANSI/NAPM IT9.11-1993, American National Standard for Imaging Media Processed Safety Ph
21、otographic Films Storage. 3 Storage hazards and concerns Useful and acceptable reproduction of records removed from inactive storage requires attention to, and precautions against, all three of the following hazards: chemical degradation, physical distortion, and magnetic corruption 2, 3, 10, 11, 23
22、. Analog and digital recordings are on media with the same susceptibilities to chemical degradation and physical distortion. They do respond somewhat differently to magnetic corruption effects. The recommendations for storage conditions minimize each of these risks. 4 Summation of storage recommenda
23、tions 4.1 Desired useful life of the recordings 4.1.1 Medium-term storage conditions Storage conditions suitable for the preservation of recorded information for a minimum of ten years. 4.1.2 Extended-term storage conditions Storage conditions suitable for the preservation of recorded information ha
24、ving a permanent value. 4.2 Recommended storage environments Atmospheric temperature and humidity conditions for magnetic media storage are summarized and tabulated in Table 1. Table 1 Storage conditions Medium-termExtended-term Equilibrium temperature, C Equilibrium relative humidity, % Alternative
25、 1: Temperature, C Alternative 1: Relative humidity, % Alternative 2: Temperature, C Alternative 2: Relative humidity, % 23 max. 20 45 20 max. 20 30 15 max. 20 40 10 max. 20 50 Physical status: Winding Enclosure Roll orientation Co-planar Protective Vertical Co-planar Protective Vertical External ma
26、gnetic field DC: Oe AC: Oe 50 max. 10 max. 50 max. 10 max. Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 12:01:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 12606:1997 2 BSI 09-1999 5 Derivation of recommended storage conditions The values in Table 1 have been derived from the extens
27、ive practical experience with photographic films, as recommended by ANSI IT9.11 for the minimization of various degradations in monochrome photographic films. Most of the same polymers and modifiers are the major components of magnetic media. Existing data on magnetic media show that the two media a
28、re subject to the same degenerative reactions, with reaction rates that are similarly controlled by storage conditions 10, 11, 23, 30. 5.1 Application of the recommendations of Table 1 5.1.1 Cycling Cycling of temperature and/or humidity increases the severity of the storage conditions, and should b
29、e minimized. 5.1.2 Environmental purity Control of air-entrained solid particles and gaseous impurities such as sulfur compounds, acidic vapors, ozone, peroxides, nitrogen oxides, ammonia, etc. are observed to accelerate chemical degradation. 5.1.3 Alternative storage recommendations For extended-te
30、rm storage, the three correlated temperature/humidity environments of Table 1 provide essentially equivalent protection to the media. The choice among the three may be based upon convenience and existing structures. 6 Chemical stability The stability of the organic carrier-matrix bearing the magneti
31、c particles must hold the composite in its as-recorded structure to maintain the reproducibility of the record. Although specific audio magnetic records may incorporate additional chemical compounds not normally found in processed photographic films, it is perhaps fortunate that the chemical stabili
32、ties of the major components are controlled by the same environmental factors, thereby justifying parallel recommendations. 6.1 Moisture content and temperature of the media All of the studies on chemical stability confirm that it is the precise moisture content and temperature of the actual media t
33、hat controls the stability 2, 10. When first placed in storage, the media may require considerable time to equilibrate to the surrounding storage environment. 6.1.1 Equilibration rates A compact roll of tape or film can achieve temperature equilibrium with its environment rather quickly, but can ach
34、ieve moisture equilibrium only by the slow molecular diffusion of moisture into or out of the face of the roll, all the way to the midplane of the tape or film 32. 6.1.2 Media enclosures Media in storage should be in a protective enclosure or in a cassette. Such enclosed recordings will require even
35、 more time to achieve a different equilibrium relative humidity. 6.2 Nature of chemical instabilities 6.2.1 Polymeric hydrolysis A major chemical degradation mechanism for most of the organic compounds present, both in photographic films and in magnetic recording media, is hydrolysis paced by the mo
36、isture content and temperature of the medium and possibly also catalyzed by some industrial pollutants1)3, 4, 10, 28, 29. 6.2.2 Magnetic particle chemical stability The inorganic magnetic materials in the media may include oxides of extended thermodynamic stability, or metallic elements potentially
37、subject to oxidation which is also facilitated by increased moisture content and/or increased temperature 23, 26, 27, 30. 6.3 Optimum extended-term storage Inasmuch as the rate effects of temperature and of equilibrium relative humidity (i.e. actual moisture content of the media itself) upon chemica
38、l degradation are cooperative, it is desirable, when maximum useful life of the recordings is important, to attempt reconditioning of the media before storage and to store at the lower range of recommended relative humidities and temperatures. 1) The actual moisture content of the media, either phot
39、ographic or magnetic, increases with increasing partial pressure of water in the atmosphere (the absolute humidity), and decreases with increasing temperature of the medium. For most materials of interest over temperature ranges near “room temperature,” this relationship, by pure chance, correlates
40、approximately with relative humidity of the atmosphere. Thus ANSI IT9. 11 and related guides recommend equilibrium relative humidity ranges. Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 12:01:45 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 12606:1997 BSI 09-19993 7 Magnetic corruption
41、 Magnetic recording is a reversible process and the magnetic pattern representing information in a record remains capable of alteration by subsequent exposure to an appropriate magnetic field. 7.1 Environmental effects on magnetic corruption All mechanisms contributing to magnetic corruption increas
42、e in activity and significance with increasing temperature. 7.1.1 Temperature effect The temperature recommendations of Table 1 have been chosen for minimizing chemical degradation over several years storage. Elevated temperatures limited to several weeks, or even days, however, can induce magnetic
43、corruption, and should also be avoided. 7.1.2 Thermal energy effects Randomized distribution of thermal energy among the particles over time can, with some probability, assist additional particles to change their magnetic sense, possibly even as directed by the juxtapositioned fields of the recordin
44、g itself 7.1.3 Magnetic field effect External magnetic fields provide an additional potential for magnetic corruption of the recordings.2) 7.1.3.1 External DC fields with a magnitude no greater than 50 oersteds (4 kA/m), acting upon audio magnetic records in storage, have generally shown no degradin
45、g effect upon analog or digital recordings.3) 7.1.3.2 External AC fields are capable of assisting a larger number of particles to change magnetization sense, and therefore the somewhat lower AC field level of 10 oersteds (800 A/m) should be observed. 7.1.3.3 External fields not only increase the lev
46、el of the noise floor, but also increase the print-through effect (see 7.2.1). An external AC field has been shown to be particularly effective in accelerating growth in the level of the printed signal. 7.1.4 External magnetic fields External magnetic fields are most frequently observed near motors
47、and transformers (e.g. commercial building elevator installations). Most of these installations are localized and therefore the field intensity falls off rapidly with separation; a few feet of separation from the source may provide protection. External fields of a more unanticipated nature may be pr
48、oduced by audio speakers, by cabinet latches, by magnetized tools, etc. 7.2 Analog recording mode Analog audio recordings strive for a signal-to-noise ratio of 60 dB-80 dB and are therefore most sensitive to low-level corrupted information. 7.2.1 Print-through is a significant problem in the storage
49、 of analog magnetic audio recordings. The imprinting field that is acting upon the most susceptible particles is coming from the adjacent layer of the recording itself. The “added noise” is thus not random but recognizable music or dialog, and therefore most distracting. 7.3 Digital recording mode Digital audio recordings provide quality reproductions from magnetic signal-to-noise ratios of about 20 dB. Accordingly, the reputed insensitivity of digital recordings to magnetic corruption has some foundation, but since digital systems usu