A digital archive (also referred to as a data archive) is usually an information system whose goal is to store different digital resources and make them available to a defined group of users. In terms of content and technology, digital archives continue to grow together with digital libraries and digital museums, which is why the term memory institution is now also used as a collective term. As in other areas referred to by the term digital revolution, the advent of digital technology brings many changes to the world of archives.
Definition of a Digital Archive
Archives, similar to libraries, serve to store media and information carriers, but above all uniquely preserved documents (such as archival materials such as administrative records) and to preserve them for posterity. Digital archives perform the same task for digital resources. They can often be found on the world wide web, but can also use local intranets, CDs and other media.
Digital archives in the broader sense include all types of digital collections, including music and video archives. Digital archives in the narrower sense try to map at least partially the holdings of a traditional archive. The variant of virtual archives or archive portals does this in a new way: Virtual archives usually do not store their archive materials but work on the holdings of other archives. This makes it possible, for example, to merge several holdings into one. Virtual archives thus place the digital archive material in a new context, while digital archives copy the original archives in whole or in part.
Digital archives can be designed in very different ways. They differ, for example, by topic, by archive owner (for example, state or private), by type/file format of the content (images, texts, videos), by access possibility (public or not public), by technical structure, by language and by interaction possibility for the users (the type of navigation and search function).
Content of a Digital Archive
In the case of archival material, a distinction is made between the possibly existing analogue object (the original archive material), the digital copy and the metadata. The digital copy can differ from the original by the data format: for example, a digitized document is more often treated as an image instead of text. Such images of texts can then usually not be searched for via the text content, but only via the metadata. The metadata describes the analogue or digital archival to make it findable, for example by specifying the author, the title and the date of exhibition, publication or production, but also by keywording the content. So-called “digital documents” also refer to digital objects that no longer have an analogue counterpart, such as electronic files.
The archival materials in a digital archive are designed for an unlimited storage period. Due to the rapid development of information and communication technology, archives have to find ways to read outdated data carriers, use outdated data and map functionalities of old programs. A formal possibility is generally binding standards; technical possibilities include emulation of system environments and migration of data. Open Archival Information System (or OAIS) has established itself as a reference model in recent years. Digital archives are often implemented as a repository.
Organization of a Digital Archive
The many individual archive pages on the WWW are often summarized and arranged by archive networks or archive portals. Archive networks are associations of several archives in the form of a common web presence. Monasterium.net connects church archives mainly from Austria, Italy and Bavaria. The advantage of such archive networks for the user is that one can search the holdings of all member archives in one fell swoop, instead of having to laboriously re-enter the search query on each archive homepage via links. Archive portals, on the other hand, only give a small overview of (selected) existing archives and at the same time facilitate access through links.
- Obsolescence: Both analog and digital data may be outdated and unreadable; this danger is greater in the case of digital archives due to constant technical development. Digital data must also remain inter-operable, i.e. the data and software of the digital archive must remain readable and processable even under other technical conditions.
- Time and cost intensity: At the turn of the millennium, comprehensive digitization of the holdings of an archive still meant high costs and enormous effort. Ten years later, digitization is far less problematic. Nevertheless, the hardware and software for the digitization process must of course first be purchased; and the maintenance of digital archives also entails costs, which, however, are difficult to estimate over a longer period. In addition, archives are faced with the task of digitizing both new and old holdings, which represents an additional medium-term effort. The time-cost factor, however, is largely offset by many other advantages.
- Protection and securing of objects: Even paper and microfilms do not last forever, and the more often a document is excavated, the faster it ages. Digital copies thus contribute to the protection of sensitive archival material. In contrast to analogue copies, there is no need to fear a loss of quality with digital copies. Archives are also legally obliged to make backup copies of their holdings. Of course, this can also be done in digital form. In the case of digital archives, however, the problem of long-term archiving is exacerbated. In addition, the digital data must be additionally protected against unauthorized access and modification (for example by viruses or hackers).
- Efficiency: If the holdings of an archive are also digitally accessible via the Internet, the research is made easier for users. Travel costs and waiting times for the removal of the archival material are eliminated. The staff of the archives has fewer visitors to look after and can devote more time to the remaining visitors as well as the archive material. The handling of archival material on both sides (users/visitors and archivists) becomes more efficient (especially through search and navigation using metadata). Even if not the entire holdings of an archive have been digitized, a user can already get an overview of the holdings in the digital archive and plan his visit to the archive.
- Space requirements: Compared to conventional archives, digital archives have a reduced space requirement, as the information of the digital copies on the data carriers is strongly compressed. Nevertheless, it is unlikely that conventional archives will completely dispense with the analogue originals and thus physically shrink. For backup copies, however, space-saving digital copies can also be considered.
Historically, archives have been administrative tools. Because archives retain and manage large amounts of personal and sensitive data, any existing national and regional archives laws overlap with many other areas of legislation. An important point here is not only the regulated access to such data, but also to protect it from change. There is currently no internationally uniform legislation on digital archives.