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The Department of Communications, Information Technology and the Arts has established a number of working groups reporting to its Corporate Management Forum. The Information Technology Working Group, in late 1999, established a subgroup devoted to digitisation of collection materials by national collecting institutions in its portfolio and other related cultural organisations in the Australian Capital Territory.
The Digitisation Subgroup met during 1999 and 2000 on a near-monthly basis and was chaired by Dr Katy Gillette, Manager of Information Technology at the National Museum of Australia. The group held its last formal meeting on 6 December 2000; it will now meet on an informal basis every 4 months. The participating institutions are:
Australian Institute of Aboriginal and Torres Strait Islander Studies
National Archives of Australia
Terms Of Reference
In recognition of whole-of-government initiatives and policies to move government services and business online, the Digitisation Subgroup was formed with the following terms of reference:
Objectives
The objectives of the group were to:
Principles of Digitisation
The following principles for digitisation programs were developed by the Digitisation Subgroup of the Corporate Management Forums IT Working Group.
Digitisation of cultural heritage materials is a complex and costly endeavour. Many issues need to be addressed by any institution embarking on digitisation programs, but the Digitisation Subgroup has identified a number of fundamental principles that can guide decisions about what and/or how to digitise. It agreed that the first two are fundamental principles, while the remaining ten are a menu from which to select depending on the goals of the program (Principle 1).
Deciding how and what to digitise will vary according to the goals of the project. Decisions about quality and quantity will be bounded by goals, priorities and available resources. For institutions that anticipate using a set of images only on the Web, then digitising at a lower resolution (quality) may be an option (but consider Principle 3). When archival (high-resolution) digital images are wanted, then perhaps fewer items (quantity) in a particular collection can be digitised and selection must be guided by clear goals, eg collection management, preservation, access and other goals. For audio and video material, bit and sampling rates correspond to resolution and the above principles apply. Ultimately, setting goals includes a cost-benefit decision-making process.
Digitisation programs should reflect the strategic and operational goals of the institution and obey policies. For example, at some institutions there is a policy that collection materials do not leave the premises to be photographed, digitised, or copied by any other means. When such policy is to be knowingly violated, risk minimisation procedures should be instituted. At a higher level, digitisation programs should reflect internal policies regarding collection access, preservation, collection management and marketing. Note that in turn digitisation policy should be driven by principles such as these.
Digitisation of collection materials can be a complex and expensive process. Thinking about future uses and needs for the digital copies we create today may help to avoid duplication of effort, using formats of limited longevity and applicability, cheap short-term solutions that are not cost-effective long-term.
The technology of digitisation, like all areas of technology, is continually changing. Regular re-evaluation of technological approaches and processes will play a role in optimising the efficiency and effectiveness of digitisation programs.
Many potential risks attend digitisation programs, from loss or damage of originals to using technological solutions that do not meet required standards. Approaching digitisation of collection materials as a series of smaller, controllable subprojects can have many advantages in minimising risks, as can good quality control procedures.
At the outset of the digitisation program it is desirable that digitisation should be seen as part of a larger, routine process rather than as an isolated, separate activity. That larger process can include:
The routine processes adopted for managing digital collections and records should preclude, or at least minimise, any double handling or unnecessary duplication of products. For example, digitising 50 images for Web presentation at a low screen resolution or, for audio, at a low sampling rate, and later re-digitising at high resolution or high sampling rate for other purposes is a waste of time and resources, and could be hard on collection materials where originals are being scanned or played again on a tape recorder.
Collecting institutions have many reasons for borrowing materials from each other, eg for exhibition purposes. In some of these cases both parties may agree that the borrower make digital copies of these items for a variety of purposes (eg condition reporting, online exhibition). It is vital that information management systems for digital materials can adequately record the provenance of these digital borrowings to avoid confusion about the custodianship.
Digitisation of cultural materials and provision of access to digital copies should comply with intellectual property legislation, with moral rights, and with cultural protocols with respect to Indigenous and other cultural groups. In turn, it is good practice to ensure that users also comply with legal and cultural conventions.
In recognition of whole-of-government initiatives and policies to move government services and business online, collecting institutions are increasingly collaborating to provide access to quality information about Australias cultural heritage. Collaboration with other institutions and commercial partners can contribute to minimising duplication of effort, improving access to digital collections, achieving efficiencies, improving knowledge about and processes for digitisation.
Digital copies are information manage them! is another way to summarise this principle. Digital copies should be part of a broader strategy to manage collections and access to those collections, to apply good information management practices to managing digital copies (eg file naming, creating database records including standard metadata, cross referencing, secure storage of physical and online digital formats, recording of any manipulations), and indeed to managing any intermediate reproductions, such as photographs. Planning for the maintenance and preservation of digital information should be part of the strategy.
Digital copies are excellent access surrogates, but not substitutes for the original item, which must also continue to be managed according to best practice.
Digital copies should faithfully reproduce the material provided for digitisation, including all faults and artefacts of the original in the first instance. Manipulation can be performed on a subsequent version to enhance the reproduction, if requested, for presentation purposes and so on. All such manipulations must be documented.
Developing minimum specifications for digitisation
The Subgroup spent the majority of its time working towards the goal of developing agreed minimum specifications for digitisation. Its most original work was in the development of the foregoing underlying principles that underpin decisions about specifications.
There was a concerted effort to develop a specifications matrix for static visual materials with one axis denoting the format of the original material was displayed (eg 4x5 colour transparency, map, original manuscript, print publication) and the other denoting the nature of the specification ( eg resolution, file formats, file naming, metadata). In the end the group re-combined all the formats of originals into one category static visual materials. It then specified minimum specifications for some parameters but recommended institutional discretion for other parameters (see below). In other words, it was shown to be difficult to set common minimum specifications across the board, and to find terminology that was unanimously agreed.
It had been intended to develop a similar matrix model for digitisation of audio and audio-visual originals, but the checklist of parameters developed for visual materials applies equally well for these other formats, with some changes of terminology.
While the work on specifications was intended to be one of the major tasks for the Subgroup, it does not seem that this activity can be taken any further. The major output has been the principles of digitisation referred to above. However, a valuable checklist of specifications has resulted and will be a useful tool.
Specifications for static visual materials
In deciding the following specifications the group worked on the assumption that:
|
Specification Area |
Suggested Minimum Specifications and Practices |
|---|---|
|
Master copy |
|
|
Delivery medium, carrier |
Any delivery medium that can be played/read, dependent upon how the organisation will use it |
|
Tonal, pixel depth (input) |
12 bits per pixel for all except microfilm and printed text where 8-bit greyscale may suffice |
|
Tonal, pixel depth (output) |
8 bits per pixel for all except microfilm and printed text where bitonal may suffice |
|
File formats |
TIFF latest version, PC bit order |
|
Compression type & level |
Uncompressed, or lossless if compression is needed |
|
Resolution (spatial dimension in pixels) |
Not below 300dpi with reference to original item, with the proviso that the scanning resolution must capture the smallest detail; spatial resolution as recommended by the California Digital Library is suitable for standard transparency and negative sizes |
|
Manipulation, enhancements, cropping |
None outside what is inherent in the digitisation process |
|
Calibration of equipment (gamma setting, tonal range, dynamic range, colour standards) for capture |
Colour standards should meet ICCC; other settings should meet appropriate international standards for PC environment |
|
Cross-platform requirements |
Specify that content can be read by PC and Macintosh |
|
Metadata (header, caption) |
Specify as per institutional needs |
|
File naming |
Each file must have a unique identifier including institution name, in a format that can be used by the institution |
|
Measurement of capture system performance/Quality Control |
Specify as per institutional needs the quality level expected of supplier (eg maximum error rate) |
|
Handling of special formats, eg concatenation/ |
Specify as per institutional needs, recognizing that it is always preferable to capture the whole work in one file |
|
Orientation |
As per original or as per institutions specified needs; where it is not clear from the original it may be necessary to advise supplier where top is, whether original is landscape or portrait, etc |
|
Polarity (pos., neg.) |
Specify as per institutions needs, usually same as original |
|
Light levels |
Specify that image capture must be carried out without exposing original to excessive light and that original should be immediately re packaged after capture |
|
File sizes, eg for digital photos |
Specify file sizes where this is necessary (particularly where other resolution definitions make no sense eg for 3D objects). A specification here may impact on other specifications (eg it may not be possible to achieve the resolution level specified within a specified file size). |
|
Documentation, batch reports, lists eg of file names, file sizes, CD nos. |
Specify as per institutions needs |
|
Handling/Care of original |
Specify according to preservation needs/best practice guidelines |
|
Labelling of carrier and packaging |
Specify as per institutions needs, noting that care should be taken in labeling not to damage integrity of the carrier |
|
Text conversion, encoding requirements |
Normally this would be a derivative - care should be taken not to lose master file; specify accuracy level, depending on need, the document type (eg ASCII, XML, plain text) |
|
Derivatives |
Many of the above areas need also be specified for derivatives |
Contacting the group
The contact for the Digitisation Subgroup is Lydia Preiss, Manager of Collection Preservation at the National Library of Australia, lpreiss@nla.gov.au .
Last modified: August 09 2004.
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