Standards for surrogates that are to be recorded in the EROMM database

This document is not intended to offer an exhaustive description of quality standards. Instead it aims at listing the essential criteria that have to be kept in mind, when reformatting information from print or manuscript to other media for preservation. You will find useful links and selected titles for further reading at the end.

Any print, manuscript or other unique item, which needs to be preserved and may be reproduced on microform or digital form. There are no limitations in type of publication or text (monographs, serials, journals, newspapers, maps, music scores, etc), language, date or provenance.

Works, whose original type of publication is digital form or microform are excluded.

(See the format for recording reproductions.)

ISO 6199:1991 Micrographics
Microfilming of documents on 16 mm and 35 mm silver-gelatin type microfilm – Operating procedures

ISO 18901:2002 Imaging materials
Processed silver-gelatin type black-and-white films – Specifications for stability

There are no generally accepted international standards for colour microfilm. Ilfochrome (former Cibachrome) seems to be only type of colour microfilm with archival quality. See http://www.microcolour.com/ilfo_test.htm for the summary of a tests performed at the Image Permanence Institute, Rochester, New York, USA (TI 10 US/e - December 1989). More on colour microfilm may be found in DIN 19058:1995-02, Farbmikrofilm - Aufnahmetechnik, Herstellen von Original-Strichvorlagen und Halbton-Vorlagen, Bewertung.

Silver halide film (16 mm, 35 mm, 105 mm, black and white, colour), safety base, first generation (or a generation accepted as replacement, sc. printing master). Production and archiving must follow international standards to ensure indefinite access. Such film is regarded primarily as preservation material which shall not to be used for other purposes. While films on a polyester base may have -depending on storage conditions- a maximum live expectancy (LE) of 500 years, films on a cellulose-ester-type base can have a maximum LE rating of only 100 years. Cellulose acetate as base of film can be the cause of loss of information recorded on that film; a more detailed description of this problem is available from the Image Permanence Institute.

Work copies (i.e. user copies) shall be produced from a second generation master (printing master).

This implies that a library will have at least two generations of microforms: A preservation master and a printing master. The latter is used to produce further generations of film including work copies.

The general physical description of the surrogate is filed in the bibliographic record in coded form. If mandatory information specified as such in the EROMM record format is missing in a record, it will not be loaded.

(Codes for physical attributes of microform masters)

Microforms that were produced before publication of current standards but which, according to the assessment of the responsible partner, fulfil their essential requirements, have been recorded in EROMM. Microforms produced at a later date, which do not conform with ISO standards but follow other standards, should carry an explanatory footnote.

ISO 18911:2000 Photography - Processed safety photographic films, Storage practices

ISO 18902:2001 Imaging materials - Processed photographic films, plates and papers, Filing enclosures and storage containers

Materials used for boxing of first generation microforms must be of archival quality. Boxes must be clearly marked and labelled.

Different types of films (polyester-based, acetate-based) need to be stored in different repositories.

For polyester-based microfilms storage temperature of 7 degrees Celsius (+/- 3 degrees Celsius, but keeping a constant temperature) and relative humidity of 25 to 40% are recommended. For acetate based films storage temperature is 3 to 5 degrees Celsius and humidity 33 to 38%.

For the storage of either type of film it is important that the temperature and humidity remain constant.

Long-term preservation requires proper storage climate and periodic inspection.

It is essential to store the printed or manuscript original and the microform surrogate in separate areas. This will help to avoid loss or damage of both in one incident (fire, water, etc.).

As yet there are only few generally accepted international standards. The present situation is one of constant change in soft and hardware. In spite of this minimal requirements for producing digital surrogates for preservation can be listed. (See the DLF‘s benchmark.)

ISO 9706:1994 Information and documentation - Requirements for permanence

ISO 16112 (=new 18926):draft Imaging materials – Life expectancy of information stored on magneto-optical (MO) discs – Method for estimating, based on effects of temperature and relative humidity

ISO 18921:draft Imaging materials – Life expectancy of information stored on compact discs (CD-ROM) – Method for estimating, based on effects of temperature and relative humidity

ISO 18927:draft Imaging materials – Life expectancy of information stored on recordable compact disc systems – Method for estimating, based on effects of temperature and relative humidity

a) Digitisation shall start from the printed or manuscript original. If digitisation is based on a microform printing master, the digital surrogate can no longer be regarded as first generation preservation master. In this case the digital surrogate must be seen as a work copy for the reader and should be recorded either jointly with the microform or independently.

b) A digital surrogate regarded as first generation preservation master must contain the image of the printed or manuscript original (image file); this allows to base citations on the surrogate in replacement of the original. Further enhancement of the digital surrogate by adding a digital content file or full text (as text file) may be added; however, these are no preconditions for recording the surrogate in EROMM.

c) The image should be scanned at a minimum of 600 dpi when bi-tonal or at 300 dpi when colour. Grayscale and colour scanning may be necessary depending on the original.

d) The institution supplying the record of the digital surrogate or the responsible partner must give reasonable assurance that all efforts will be made to preserve it. This includes quasi lossless migration of files following changes in soft and hardware. The history of migration should be recorded in the file header.

e) The digital surrogate must be accessible to the interested public. This does not mean access free of charge.

f) To ensure that the digital surrogate will be retrievable indefinitly a persistent identifier shall be used, which must be the same for first and second generation files of the surrogate as well as for any access version. Extensions of the persistent identifier may be applied to distinguish the different versions. Online linking to the surrogate‘s access version shall be bases on the persistent identifier.

The general physical description of the surrogate is filed in the bibliographic record in coded form. In case mandatory information specified as such in the EROMM record format is missing in a record, it will not be loaded.

(Codes for physical attributes of digital masters)

The responsible partner will supervise adherance to such minimal requirements.

As yet there are only few accepted international standards for storage of digital surrogates. Existing standards for storage of electronic data carriers shall be respected.

In view of present developments in electronic data carriers no universal criteria can be given for their storage. Avoiding harmful environments cannot in itself provide for longterm preservation. Instead periodic migration of files following changes in soft and hardware will be required (see 4.2.d).

ISO 18923:2000 Imaging materials Polyester-base magnetic tape – Storage practices

ISO 18925:draft Imaging materials Optical disc media – Storage practices

It is essential to store the printed or manuscript original and the digital surrogate in separate areas. This will help to avoid loss or damage of both in one incident (fire, water, etc.).

Read our concise introduction to cataloguing of preservation surrogates. No international register of surrogates such as EROMM can live up to its role as an instrument of coordination without the diligent work of cataloguers, who are aware of the minimal set of information required. Without them the production and archiving of high quality surrogates might fail to be a contribution to saving the worlds intellectual and artistic heritage.

(Summary on Cataloguing preservation surrogates.)

(R-RDM : Recommended elements in the bibliographic record of a digital surrogate)

In this section EROMM wants to give examples of best practice in production, storing, handling and using surrogates. It is understood that this cannot be more than a selective list of practice known to members of EROMM. If you want to propose another example of best practice please contact the secretariat.

Microfilm Reading Room The Royal Library - National Library of Sweden has a reading room specially adapted to microforms, which can serve as a model for other libraries. - more -

Digital Library Federation: “Benchmark for Faithful Digital Reproductions of Monographs and Serials” 2001-2002
(http://purl.oclc.org/DLF/benchrepro0212)

ERPANET project on preservation of cultural heritage and scientific digital objects
(http://www.erpanet.org/)

Image Permanence Institute
(http://www.imagepermanenceinstitute.org/)

International Organization for Standardization, Technical Committee 42 — Photography, WG5 - Physical properties & image permanence of imaging materials
(http://www.pima.net/standards/iso/tc42/wg05.htm)

Long-term Retention of Digital Research Materials / Research Libraries Group
(http://www.rlg.org/longterm/)

National Preservation Office serving libraries and archives in the United Kingdom and Ireland
(http://www.bl.uk/services/npo/npo.html)

International Imaging Industry Association / IT10 - Electronic Still Picture Imaging
(http://www.i3a.org/it10.html)

International Imaging Industry Association / IT9 - Physical Properties and Permanence of Imaging Materials
(http://www.i3a.org/it9.html)

Safeguarding our documentary heritage / UNESCO
(http://www.culture.fr/culture/conservation/dswmedia/en/index.html)

Sciences et patrimoine culturel : portail de la conservation-restauration des biens culturels / Ministère de la culture et de la communication
(http://www.culture.gouv.fr/culture/conservation/fr/)

see Comité européen de normalisation (CEN), national members
(http://www.cenorm.be/aboutcen/whatis/membership/members.htm)

American National Standards Institute (ANSI)
(http://www.ansi.org/)

DFG-Merkblatt Erhaltung gefährdeter Bibliotheksbestände
(http://www.dfg.de/forschungsfoerderung/formulare/download/1_45.pdf)
mit Hinweisen
(http://www.dfg.de/forschungsfoerderung/formulare/download/1_451.pdf)

DFG-Merkblatt Verfilmung historisch wertvoller Zeitungsbestände
(http://www.dfg.de/forschungsfoerderung/formulare/download/1_44.pdf)
mit Hinweisen
(http://www.dfg.de/forschungsfoerderung/formulare/download/1_441.pdf)

Guides to Quality in Visual Resource Imaging / Council on Library and Information Resources, 2000
(http://www.rlg.org/visguides/)

LIBER Workshop - Microfilming and Digitisation for Preservation, 2003 This has been one of the more important events recently, bringing together collection managers in libraries and archives, managers of preservation and digitisation projects, microfilming and digitisation companies. Papers given at the Koninklijke Bibliotheek, The Hague are available on the KB's site. A very useful selection of relevant (recent) literature and websites, mostly with links to the original site can be found on the same site.

Preserving Digital Information / Research Libraries Group
(http://www.rlg.org/ArchTF/tfadi.index.htm)

Protection et mise en valeur du patrimoine des bibliothèques : Recommandations techniques / Direction du livre et de la lecture, Paris 1998
(http://www.culture.gouv.fr/culture/conservation/fr/preventi/guide_dll.htm)

J. M. Reilly, IPI Storage Guide for Acetate Film, New York 1993

J. M. Reilly, Storage Guide for Color Photographic Materials, New York 1998

RLG Archives Microfilming Manual / Research Libraries Group, 1994

RLG Preservation Microfilming Handbook / Research Libraries Group, 1992