Collection Management Policy - Appendix 4: Preservation Issues

A. Questions of definition

Conservation is taken to mean those steps and policies taken to maintain and / or repair (an) individual item(s); whereas preservation refers to those managerial, and technical steps involved in retaining the information content of library materials in all formats, so as to maximise the useful life of that information. 

B. Preservation options

In the sense above, preservation encompasses conservation, but also extends much further, and includes such issues as: 

1. Books,  archival / physical documentary material (i.e. paper and parchment):

  • the discarding of material after a particular length of time; and the steps necessary to be taken to manage that material through to that point of discard;
  • the discarding of material after intensive use; to be replaced by another physical copy;
  • the preservation of the information within a book or document, by surrogacy; and the retention or disposal of the original;
  • the conservation of the (physical original) book or document (e.g. by de-acidification) because of the importance (however defined) of that original copy;
  • the discarding of material, and its substitution by a web-based source of information.

Surrogacy here can include: microfilming; photographic prints; photocopying; in-house digital copy, though in each case, the questions of preservation and conservation are merely pushed back from one format to another.

It should also be remembered that, in many instances, reformatting is not a neutral activity, particularly in moving from certain physical documentary forms (e.g. book) to, say, microfilm, in that the change in physical embodiment of the verbal text, alters textual connotations. 

2. Preservation options for photographic material, including glass-plate negatives); microfilm, and microfiche

Surrogacy techniques here can include: copy reels, copy prints; copy microfilm / fiche, digital copy, though again in each case, questions of preservation / conservation are merely pushed back from one format to another.

3. Motion picture film

Surrogacy techniques, if required, primarily indicate digital copying.

4. Recorded sound materials (33/45/ 78 rpm discs; reel-to-reel; tape cassettes.
(For CDs, see digital resources.)

Surrogacy techniques primarily indicate digital copying. The prompt copying of recorded sound materials is particularly recommended by the National Library of Canada (1).

5a.  Digital resources

Digital resources bring different problems with them, depending on how / when / by whom they were created.

Of the digital resources held, some were born digital (e.g. CALAIS)  some are turned digital (e.g. pictures on LEMUR); some are a mixture of both (e.g. the LEMUR site as a whole, with search engine, etc.)

The Library & Special Collections however, also holds material that was commercially produced and that was born digital (e.g. floppy discs, CDs in textbooks) over which there may be copyright and IPR issues (2) but which information the library may wish to hold in perpetuity.       

Digital preservation (time-limited or in perpetuity) strategies (see C6 below for comment) include:

  • total deletion when no longer of any use (e.g. obsolete, superseded  information)
  • emulation (techniques for overcoming obsolete hardware and software by imitating obsolete systems)
  • migration (the movement between media, eg disc to CD; CD to copying / absorption in the Storage Area Network(SAN))
  • reformatting (from one file format to another)

5b. Digital resources: comments

It is currently accepted that there may never be a ‘single, definitive strategy’ for digital preservation, but that a variety of approaches may be needed.  

Presently, images from the ‘created digital’ resources  produced by Special Collections, are also saved on CD, in standard, widely accepted formats (e.g. JPEG; PDF); and, in those instances where the images have been incorporated into a wider web resource, that site as a whole is regularly backed up by the Directorate of Information Technology. Whether this regular backup arrangement will remain satisfactory is an issue we need to discuss with our IT colleagues.

Most recent guidance approves of the use of CD-R for preservation purposes; however, CD-RW is ‘based upon a different recording process to CD-R, and is not recommended for archival storage(3).     

What is essential is the systematic adoption and application of metadata (and metadata standards, e.g. Dublin Core) not just to ensure ‘resource discovery’ but essentially to provide a record of how the data was originally captured and formatted, and what modifications may have been made to it.  (This is already a requirement of some external funding bodies.)  This should also partially address interoperability issues.

C. Major challenges

Loss by theft, flood or fire remains real, and must be addressed via disaster planning. But there are other, more subtle, materially inherent  threats to the preservation of information.
  
1. Whilst accepting that printed books present a number of inherent conservation problems (mostly relating to the binding and/or the attachment of text-block to binding, or damaged leaves), it is nineteenth- and twentieth-century material that causes the greatest concern amongst research libraries. The acid quality of the paper is leading to what is known as the ‘brittle book’ problem in books ranging in date from the 1840s to well into the twentieth century. (4)  

2. Photographic collections are particularly prone to damage through handling; the emulsion side of any photographic image is particularly sensitive.  Microfilm reels are prone to chipping, splitting and cracking.

3. Motion picture films are subject to fading, though the extent of this deterioration depends on the chemical composition of the film. Cellulose nitrate base film (used primarily from 1900 to 1939, but in some cases up to the early 1950s) is unstable and highly flammable. Shrinkage, brittleness and scratching are frequently found types of film damage. ‘Sticky tape’ syndrome (caused by hydrolysis) is a major recognised problem with video tapes.

4. Dust and foreign matter deposits on any sound recordings can cause abrasiveness and encourage hydrolysis. Deformation (warping or stretching) is also a recognised problem with sound recordings, as are print-through and signal degradation on most tape recordings.

5. Many microfilms are on acetate-based stock. This is not of ‘archival’ quality, whereas it is claimed that Black & white, silver gelatine film  has a usable life of >250 years. (5)    It is recommended that the Library and Special Collections check the quality of its microfilm stock.

6. The predominant problem with digital resources is not its potential uselessness (in terms of its data) but technological obsolescence, whereby data cannot be read or meaningfully displayed on-screen.

7. (Video)tape as an archival medium: ‘Magnetic tape is not considered a good long-term storage material for archival material. In fact there is no good archival medium for the long-term storage of video.  The archivist is therefore faced with the problems of maintaining obsolete equipment and having to copy or transfer material to a newer tape format or a different type of medium’.

D. The (growing) size of the challenge

1. Printed books

The possible movement of the cut-off date for the permanent retention of printed books and journals to 1900 would involve at least 78,500 vols falling within the ‘brittle-book’ period (i.e. from 1840 forward), though that is not to say that they will necessarily be made of the type of paper that might render them brittle.  (See D2 below).       

Moreover, cut-off dates change. It is a reasonable assumption that the date will slowly roll forward. It certainly does not follow that if a text is to be permanently retained, then it will immediately go into Special Collections. It may be many years before it does so (if at all). Actions taken to best guarantee such a book’s permanent retention as a (physical) book need to be taken long before it is taken into Special Collections. 

Printed books, particularly 1840 onwards, for possible or definite permanent retention.

1840-<1901

University Library (excl. Special Colls)

Special Colls

Total

 

54500

24000

78500 (note: subject to revision)

2. Special Collections is currently responsible for c.4000 archive collections.

The percentage of post-1840 material within AU archives is presently unknown, but the Public Record Office calculates that, overall >33% of their holdings are of this vulnerable date.

However, not all post-1840 documentary material is on ‘brittle’ paper.  A recent major NPO Assessment Survey (6) (not including University of Aberdeen collections) indicated that 39% of materials from 1850-1900 was on ‘brittle’ paper; 31% from 1900-1950was brittle; 12% of material >1950 was brittle.

A crude extrapolation from this suggests that we have c. 31,000 pre-1901 items actually constructed of brittle paper.

3. Photographic Collections

glass-plate negatives, lantern slides and prints.

Special Collections:
Lantern slides: 12 linear metres
Glass-plates : 6 linear metres

George Washington Wilson Coll:
c.40,000 glass-plates

4. Microfilm reels; microfiche collections

Special Collections:
26 linear metres
University Library:
250 linear metres

5. Motion picture film

Motion picture film is contained within several collections and is at present unquantified.

6. Recorded sound materials

Special Collections:
Reel-to-reel (single largest collection being BBC programme recordings on deposit): 28 linear metres of shelving
University Library:
c. 1800 videocassettes/tapes.

7. Digital resources (created digital)

University Library:
DVD: 19 linear metres

8. Digital resources (mainly on Library, Special Collections and Museums web sites)

These have not been quantified, but comprise a variety of resources based on the collections of the University and other organisations and individuals. Most are images taken from ‘real’ books, papers or artefacts. Although most are not ‘unique’, they would be very expensive, if not impossible, to recreate if all our digital versions were lost. As with our other collections, these are part of our core business and this investment requires to be protected.

E. Environmental conditions for storage

medium

temp oC

humidity  (R/H)

light

paper & parchment (infrequently handled) (7)

13-16

45%-60%

 

motion picture film (8)

<10

<30%

 

videotapes (9)

>7

20%-30%

 

sound recordings (discs, open tapes) (10)

15-20 (and not >20)

25%-45%

 

sound recordings (audio cassettes) (11)

10

20% - 30%

 

Photographic material (12)

below 20

30%-40%

 

And an extended excerpt from the National Archives: Care, Handling and Storage of Removable Media (2008):

All materials should be stored in an environment which provides protection from direct sunlight and ultra-violet light, and is free from chemical or particulate atmospheric pollutants. The environment should not be subject to rapid fluctuations in either temperature of humidity.

Storage areas for magnetic media should not contain large electrical devices or other equipment which may produce magnetic fields, and the ambient stray magnetic field intensity should not exceed 4000 Amperes/metre.

Recommended environmental conditions are provided for both short- and long-term storage. Note that for electronic media, ‘long-term’ may be less than 5 years.

Short Term Storage

Media

Temperature

Relative Humidity

Flexible Magnetic Disks

10-51.5ºC

20-80%

Digital Audio Tape (DAT)

5-45ºC

20-80%

Digital Linear Tape (DLT)

16-32ºC

20-80%

Ultrium Linear Tape Open (LTO)

16-32ºC

10-80%

Other Magnetic Tape Cartridges

10-45ºC

20-80%

CD-ROM/R/RW

10-50ºC

10-80%

DVD-ROM/R/+R/RAM/RW/+RW

10-50ºC

10-80%

Solid State Media

10-50ºC

20-80%

Mixed Collections

16-32ºC

20-80%

Long Term Storage

Media

Temperature

Relative Humidity

Flexible Magnetic Disks

18-22ºC

35-45%

Digital Audio Tape (DAT)

5-32ºC

20-60%

Digital Linear Tape (DLT)

18-26ºC

40-60%

Ultrium Linear Tape Open (LTO)

16-32ºC

20-80%

Other Magnetic Tape Cartridges

18-22ºC

35-45%

CD-ROM/R/RW

18-22ºC

35-45%

DVD-ROM/R/+R/RAM/RW/+RW

18-22ºC

35-45%

Solid State Media

18-22ºC

35-45%

Mixed Collections

18-22ºC

35-45%

F.   Preservation Assessment Survey (Preservation Advisory Centre): archives provisional report

Special Collections has recently adopted the National Preservation Office’s  Preservation Survey methodology, (13) and has undertaken separate surveys of its printed book and archive collections.

The survey of the archive collections revealed that:

  • much of the archive collection (in its entirety) is badly packed. Boxes are usually stood on their ends, rather than lain flat.  (This was done because of space shortages.)
  • large numbers of boxes are inappropriately packed, and overpacked
  • boxes made of the wrong materials have been used for the packing of materials
  • much intervention work is going to be needed to flatten papers, many of which are still retained in bundles or (worse) folded.  (This is probably how they arrived in AU).
  • much basic cleaning of the papers is needed, to remove particles of dust
  • the rolled maps and plans are a professional challenge
  • for some collections, there are only very basic listings available. Cleaning and reorganising any collection will have a consequential effect on archive cataloguing demands.  

G. Deacidification and acid paper: comments

There are a number of techniques available to tackle paper acidification, though larger libraries have usually entered into contracts with commercial firms to carry it through; the major reason being the high volume of material to be treated.

The attraction of the process is its relative cheapness. The costs of reformatting can be over 10 times higher than those of deacidification (14); and de-acidification retains the physical original. (See comments above at B.1 above).  

Although deacidification presently offers the best solution to the problem caused by acidity in the paper that can lead it to become brittle, there other steps, if not entirely preventative, that can be taken, to slow down the process.  The temperature and R/H should be maintained towards the lower point of the recommended conditions; and any fluctuations in R/H kept to a minimum. Minimal lighting, and boxing (where appropriate)  will also retard the process.  

H. Provisional recommendations: printed books

Although it is implicit in the actions taken by Library & Special Collections it should be made explicit that wherever and whenever possible, texts for permanent retention should be kept in their original format, even if it is necessary to create a surrogate for consultation use.

  • The University Library (and other sites) should organise an NPO Preservation Assessment Survey, particularly, but not exclusively, to assess the extent and advance of ‘brittle paper’ in nineteenth- and twentieth-century books (and periodicals).  Any such survey should include an assessment of the physical state of microfilms / microfiche, and other forms of media.   
  • At a strategic level, the University Library should investigate (via SCURL) whether Shared Preservation in Scotland (SPIS) is likely to revive. (The last planning reports appear to have been in 2001.)
  • The institution should ensure that there is no slippage in the planning of the new library in the adoption of the optimal conditions for the storage of material for permanent retention.
  • Re-introduction of simple (summer) training session(s) on the handling of documentary material, and what to do / not to do with a damaged book. (The Bindery staff should be involved in teaching these sessions.)  
  • The long-term cleaning project of Special Collections areas be maintained.
  • A programme of boxing (in archival-quality materials) of already damaged or vulnerable material to be permanently retained be investigated, as a simple way of providing a buffer (this has been adopted to good effect in TCD).

I. Provisional recommendations: general

All sections of Library & Special Collections to maintain and update their disaster procedures. 

J. Trusted Digital Repository

The establishment of a coherent and defensible set of standards for a digital preservation strategy for Library & Special Collections will undoubtedly assist in any attempt to establish 'Trusted Digital Repository' (15) status, in that it should demonstrate commitment to a range of administrative responsibilities (including community-agreed standards and best practices; risk management; and donor / depositor agreements; financial sustainability; and technological suitability including, of course, a preservation strategy).

However, it is perhaps beyond the remit of Library & Special Collections as such (or sections therein) to aim for Trusted Digital Repository accreditation (when such accreditation standards and awarding bodies are agreed upon), and rather, a decision ought to be made more widely, in conjunction with the Directorate of Information Technology.

K.  Principles underpinning a Digital Preservation Strategy for Special Collections

Digital capture

The now rather geriatric concept of ‘fitness for purpose’ still applies. This essentially means that the majority of digital images of three-dimensional objects (including books and archival material) captured by or on behalf of Special Collections are to be captured at preservation standards (16). This still equates roughly at 600 dpi (full colour). 

Special Collections is not currently able to offer ‘preservation standard’ capture for audio and video materials in digital format.  This state of affairs needs to be rectified.

Digital storage (capture standards)

Special Collections should maintain its approach in using internationally-approved open standards for image file format. (That is, TIFF. Though a watching brief should be kept on JPEG2000 and ADOBE’s ‘digital-negative’ file format for archival format camera raw data ).   

Digital storage (software)

Digital preservation is of crucial concern for the growing resources within the Library & Special Collections.  These resources include an increasing quantity of digital content – text, images, audio and video.  To date this has been managed and delivered in an ad hoc manner, depending on the technologies and expertise available at the time, ranging from the Bestiary Project (completed in 1996) implemented using html, to the George Washington Wilson Photographic Archive (revamped in 2005) loaded into iBase (based on MS SQL).  Each of these separate projects has required an element of individual web development, database design and image manipulation. This is an unsustainable approach and a mechanism for reducing the number of systems in use and for addressing digital preservation issues was sought, leading to a decision in 2006 to purchase DigiTool.

DigiTool is an enterprise solution for the management of digital assets in libraries and academic environments.  It is supplied and maintained by Ex Libris, the company which provides our current Library Management System and e-Resource Portal.  DigiTool will start to address the digital preservation issues raised here, and allow the Library & Special Collections to manage, preserve and share its currently disparate digital collections within a single environment.

DigiTool is an ideal solution for the deposit, management and delivery of this material.  It consists of a number of modules:

The DigiTool Repository stores and manages the digital objects and associated metadata.  The metadata is stored in an Oracle-based database, and the digital objects in a network file system or on remote systems accessible via URLs.

Administrative modules are used by staff and system administrators - the Ingest module handles the loading of objects into the Repository; editing of descriptive or other object metadata (for example, technical or preservation metadata) is accomplished through the metadata editor, Meditor; using the Collection Management module, staff can organize objects into structured collections that facilitate end-user navigation.

The Resource Discovery Module allows users to search object metadata or the full text of documents, navigate collections, and view digital objects.  Access to the objects can be controlled by user status or IP address.

The Deposit module supports the Web-based uploading of digital objects such as theses, exam papers, and learning objects by non-library staff.

DigiTool also includes utilities for conversion of data from other sources.  MySQL data could be exported, mapping rules defined, and the data then loaded into DigiTool using a transformer provided by Ex Libris.

The DigiTool architecture is based on technologies such as Web services (SOAP), XML, XSD, XSL, ODBC, Unicode, and JPEG 2000 and supports MARC 21, Qualified Dublin Core, METS, Z39.87-2002 - Technical Metadata for Digital Still Images, OpenURL, Z39.50, and OAI-PMH.  Authentication can be via a local user database or via LDAP.
DigiTool provides Library & Special Collections with a single mechanism for the management of most of our digital resources and enable easier forward migration as technologies evolve.

Digital storage (hardware)

The best portable storage medium remains CD-R (not CD-R/W); and at the highest quality available. 

The main storage medium is the University’s network storage. This is mirrored at remote locations and backed up nightly by DIT. Security is maintained by DIT as part of its Business Continuity operations.

Special Collections does not currently have the facilities for the routine transfer of the informational contents of cassette tapes, video tapes or cine film onto digital media. Provision of facilities to enable these activities should be investigated.

Metadata

Issues surrounding metadata relate as much to management and organisation as to the identification and recording of technical data.  Metadata should be recorded for all digital material held for other than a transitory period.

Special Collections needs to prepare an ‘archival information package’ which consists of the digital image + technical metadata + descriptive metadata (i.e. description of the object or scene etc.)  These elements need systematically to be gathered and at close time proximity, so that such a ‘packet’ of information can be created. This is a management issue that needs to be addressed.

On metadata itself, standards continue to evolve, with Dublin Core currently remaining as the front-runner.

The management, particularly of the generation and recording of data in Dublin Core’s metadata elements needs attention. The recording of metadata and the decision-making processes listed above should be applied across Special Collections. 

Interoperability

Provided that Special Collections maintains its policy of keeping to ‘industry standard’ software; and provided it is able to draw up tighter regulations for the creation and recording of metadata, questions of interoperability (which are arguably not directly relevant to digital preservation, but are to ‘Trusted Digital Repository status) will be minimised.

Storage

The environmental conditions under which CDs should be stored are recorded elsewhere in this document.

Special Collections should introduce a sampling timetable of its CDs, regularly to check their quality.

Environmental questions relating to storage on the SAN are beyond the remit of Special Collections.

Migration within the SAN will be subject to negotiation.

Footnotes

1. National Library of Canada. The Preservation of Recorded Sound Materials
http://www.collectionscanada.ca/6/28/s28-1017-e.html

2.  ‘The duration of IPR in electronic materials will often extend well beyond commercial interests in them and the technology which was used to generate them. Long-term preservation and access may require migration of the material into new forms or emulation of the original operating environment: all of which may be impossible without appropriate legal permissions from the original rights owners of the content and underlying software.’  (Our italics).  From : M. Jones & N. Begrie, Preservation Management of Digital Materials, 2001. 

5. IFLA Principles for the Care and Handling of Library Material.
http://www.ifla.org/VI/4/news/pchlm.pdf

6. Re:Source. INFOSAVE Project Report. http://www.bl.uk/services/npo/pdf/infosave.pdf

8. Library of Congress. Care, Handling and Storage of Motion Picture Film
http://www.loc.gov/preserv/care/film.html

10. National Library of Canada. The Preservation of Recorded Sound Materials.
http://collectionscanada.ca/6/28/s28-1019-e.html

11. Library of Congress. Cylinder, Disc and Tape Care in a Nutshell
http://www.loc.gov/preserv/care/record.html

13. The survey sample of 400 items is generally regarded as statistically robust.

15. See RLG’s website for many references.

16. National Information Standards Organization: A Framework of Guidance for Building Good Digital Collections. 2004.

17. The official body, Canadian Heritage gives up to 100 years’ lifespan for ‘factory-stamped’ CDs; up to 200 years lifespan for CD-Rs.

A. The Media Selection Scorecard

The scorecard approach described here provides a simple method for evaluating currently available media against a series of selection criteria. Each medium should be scored against the criteria on a scale of 1 (does not meet the criterion) to 3 (fully meets the criterion). As a general rule, no medium which scores less than 12 should be considered.

An example scorecard, comparing some common media types, is shown below:

Media

CD-R

DVD-R

Zip Disk

3.5” Magnetic Disk

DLT

DAT

Longevity

3

3

1

1

2

1

Capacity

2

2

1

1

3

3

Viability

2

2

1

1

3

3

Obsolescence

3

2

2

3

2

2

Cost

3

2

1

1

3

3

Susceptibility

3

3

1

1

3

2

Total

16

14

7

8

16

14

The evaluation process should fully take into account variations within a media type. For example, a number of different dye and metal layer combinations are available for CD-Rs. In this example, CD-Rs with a gold reflective layer and phthalocyanine-based dyes have been assessed, since recent research suggests that these are the most stable, and have the greatest life span.

In situations where multiple copies of data are stored on separate media, it may be advantageous to use different media types for each copy, preferably using different base technologies (for example, magnetic and optical). This reduces the overall technology dependence of the stored data. Where the same type of media is used for multiple copies, different brands or batches should be used in each case, to minimise the risks of data loss due to problems with specific manufacturers or batches.

Taken, and slightly amended, from National Archives, Selecting Storage Media for Long-Term Preservation (Digital preservation guidance note, 2). (London, 2008).