Franziska Frey from Havard University gave two lectures this morning on Preservation Strategies for Digital Image Collections. She explained the daily activities of those who take care of team of about 100 persons taking care of 70 millions books, 10 millions photographs, more than 100 000 maps but also specimen, painting and other objects. The archive contains now 160 TB of data, about 46 million files which are of course in many formats, image, audio, text, digitised books, website, biomedical images stacks, etc. For each file four copies are kept, automatically replicated to 3 different geographic locations. Franziska Frey shared some important lessons about the logistics and good practices of digital preservation.
A race over time. Preserving these documents is a race over time. For instance, for preserving audiovisual material you have only a 20 year window. After 20 years you don’t find the skills or the equipments anymore. It could be argued that acceleration in terms of format change is continuing.
Logistics and workflows. Concerning digitisation processes, she stressed the importance of logistics to deal with large digitisation campaign. Interdisciplinary teams of curators and image specialists meet to decide of the different digitisation workflows and try to evaluate the time for each of them. Sometimes, doing adaptations permitting to move to a fast workflow is the best solution. Sometimes, given the complexity of the material involved, slower workflows are in the end the fastest. Some of the workflows imply building dedicated scanners.
The digital preservation market. Digital preservation is potentially big market, but most actors do not have enough money to conduct large scale digitisation campaign. People in charge of preserving the data have usually very high expectations on the quality of the digitisation processes. The big companies (Hollywood, Google, Amazon, etc.) producing or gathering content seem more and more aware of the necessity of integrating digital preservation in their strategy. It is crucial to think about digital preservation since the beginning of digital creation processes.
Responsibility. Ultimately, this is a question of responsibility. The UNESCO’s “Guidelines for the Preservation of Digital Heritage”, published in 2003, made very clear that “Digital preservation will only happen if organisations and individuals accept responsibility for it”. To succeed, you need to make clear who is responsible.
Stewardship. In addition, the digital preservation staff has to work as a steward discussing with rights holders, collection managers, repository preservation staff, caters of expertise, auditors, content users and their communities. Stewardship implies long-term management of heritage materials (digital objects) through collaboration, throughout all phases of the object life cycle.
Image quality. Image quality may vary a lot in digitisation projects. It is imperative that the person involved in creating image materials, whether born digital or digitised, has a good knowledge of imaging. This is usually the weak point of most projects. A project was conducted for benchmarking american museum practices and defining future needs (http://art-si.org). The image quality is dependent of future use of the material. Ideally, this needs to be defined in the beginning of the digitisation project. In some cases, institutions needs to “redigitise” because they did not offer a sufficient quality for the users who use the archive. However, in many cases, users do not have the visual literary to judge about image quality. They do not know what they can demand in terms of image quality.
Usages of reproduction material. Ultimately, image quality is linked with the usage of the reproduction material. Reproduction of cultural heritage materials can be used for on-line databases, posters, calendars, postcards, exhibition catalogues, education, conservation. Each of the usages have their own requirements. It is of interest to limit the number of times an artwork is imaged as it can potentially be a source of damage for the artwork. So, again, the right decision must be taken by the time of the digitisation.
Document, document, document. Workflows need to be documented with great precision. This is very important in terms of trust.