BS-6872-1987.pdf
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1、BRITISH STANDARD BS 6872:1987 Specification for Visual densities of diazo and vesicular second-generation microforms UDC 778.14:773.71:771.537.4 Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 10:17:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6872:1987 This British Standard, having been
2、prepared under the direction of the Documentation Standards Committee, was published under the authority of the Board of BSI and comes into effect on 28 August 1987 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference DOT/16 Draft for comment 84/65217 DC
3、ISBN 0 580 16123 4 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Documentation Standards Committee (DOT/-) to Technical Committee DOT/16, upon which the following bodies were represented: British Broadcasting Corporation British Coal B
4、ritish Computer Society British Library (Humanities and Social Sciences) British Micrographic Manufacturers Association British Photographic Association Business Equipment and Information Technology Association Drawing Office Material Manufacturers and Dealers Association Electronic Engineering Asso
5、ciation Her Majestys Stationery Office Ministry of Defence National Association of Microfilm Bureaux National Centre for Information Media and Technology (Cimtech) Society of British Aerospace Companies Standing Conference of National and University Libraries The following bodies were also represent
6、ed in the drafting of the standard, through subcommittees and panels: Her Majestys Treasury Public Record Office Amendments issued since publication Amd. No.Date of issueComments Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 10:17:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6872:1987 B
7、SI 12-1999i Contents Page Committees responsibleInside front cover Forewordii 1Scope1 2Definitions1 3Diazo duplicates1 4Vesicular duplicates1 Appendix A Methods of measurement2 Publications referred toInside back cover Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 10:17:03 GMT+00:00 2006, U
8、ncontrolled Copy, (c) BSI BS 6872:1987 ii BSI 12-1999 Foreword This British Standard has been prepared under the direction of the Documentation Standards Committee. It is based on ISO 8126:1986 “Micrographics Diazo and vesicular films Visual density Specifications” published by the International Org
9、anization for Standardization (ISO). For many years there have been standards for the densities of silver films, but, until recently, it has not been possible to specify the densities of diazo and vesicular films because of the lack of suitable methods of measurement. A method for measuring their vi
10、sual densities has now been developed and is set out in Appendix A. A method for measuring their printing densities, which vary with the spectral sensitivity of the receiving material and the spectral energy of the printing illumination, has not yet been developed. A British Standard does not purpor
11、t 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 cov
12、er, pages i and ii, pages 1 and 2, an inside back cover 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. Licensed Copy: sheffieldun sheffieldun, na, Tue Dec 05 10:1
13、7:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6872:1987 BSI 12-19991 1 Scope This British Standard specifies values for the visual diffuse density of diazo films and the visual projection density of vesicular films. It applies only to second-generation microforms (duplicates), including roll fi
14、lm, sheet film and aperture cards, made from first-generation microforms of source documents and COM (computer output microforms). Methods of measurement are given in Appendix A. NOTEThe titles of the publications referred to in this standard are listed on the inside back cover. 2 Definitions For th
15、e purposes of this British Standard the following definition applies. ISO visual transmission density the density obtained when: a) the spectral products of the measurement system are the product of the relative spectral power-distribution of CIE illuminant A and the relative spectral luminous effic
16、iency in photopic vision V(); b) the densitometer influx is the ISO transmission densitometry illuminant SH (which is CIE illuminant A modified in the red and infra-red regions to protect the specimen and optical components from excessive heat). 3 Diazo duplicates 3.1 Source documents When measured
17、by the method given in A.2.1, the minimum visual diffuse density of diazo duplicates of source documents shall be above the films minimum achievable density (Dmin) and below 0.15: a) in the clear area of the image of positive-appearing duplicates (2P); b) in the clear areas, if measurable, of negati
18、ve-appearing duplicates (2N) or on a 6 % reflectance patch of a control target. NOTEThe most satisfactory duplicates are generally produced by printing a density area of 0.35 on the diazo film from a density area of 0.35 on the silver master. 3.2 COM When measured by the method given in A.2.1, the m
19、inimum visual diffuse density, if measurable, of negative-appearing diazo duplicates (2N) of COM shall be above Dmin and below 0.15, and the background density shall be not less than 1.30. NOTEPositive-appearing diazo duplicates of COM are not recommended. 4 Vesicular duplicates 4.1 Source documents
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