1The idea of prometheus (http://www.prometheus-bildarchiv.de) was born in 2001 to fulfil an important need for art history, archaeology and other cultural sciences that rely on the image as the main medium of discourse – a digital image archive for research and education. With considerable funding from the German Federal Ministry of Education and Research from 2001 to 2004, we were able to put the ideas into practice.

2Since 2002, prometheus has enabled a convenient search for images (550.000 as of October 2008) on a common user interface that joins various image archives and databases (48 as of October 2008) with different focuses put up by university institutes, research facilities, museums and other institutions. Prometheus continuously increases in volume because of new image databases being integrated. Each database has its own specific focus. So the whole spectrum of the Arts and cultural sciences is on view in prometheus : from attic vases and ancient sculpture via gothic cathedrals and famous Italian masters to modern and contemporary art and new media. Historic postcards from the 19^th century and 2 000 videos amplify the archive’s scope.

Approaches

3The goal was not to stick to old slide-archive-traditions and to maintain databases at every single institute but to pool the resources of these institutions to make as many good quality, high-resolution digital images accessible as possible for research and education on a grand scale. Therefore, the main purpose was and still is to connect various heterogeneous and topographically distributed digital image databases via internet similar to bibliographic network systems but with a different approach : individuality instead of standardisation.

4Within the last years and decades many convincing propositions were made to standardize and normalize the subject cataloging of artworks2, as just recently by the Deutscher Museumsverband by introducing the central exchange-format museumdat3. Certain rules prove reasonable, but the setup of objective and universal criteria for the documentation of each artwork is an almost unsolvable task as each subject cataloging is relative and the result of a certain understanding of art and of a contemporary methodical discourse4. The artworks’ registration in a database can be considered as a linguistic reproduction of the artwork5. And we would like to leave this to the databases and their certain regulations.

5A decision for heterogeneity does not mean at the same time that it is a decision against a succinct subject cataloguing within a database and also against the use of thesauri and dictionaries, which advance a consistent subject cataloging by defining certain terms and ideas (e.g. location). In this respect prometheus does not try to impose a particular database upon all partners or enforce particular standards. The only precondition to enter into a cooperation is that the database defines three basic elements, namely the work’s title, the image itself and the copyright information. XML is used as the only web-based standard that does not depend on any further specification. Our central server holds profiles of the individual databases we work with. These profiles specify how the consultation of each single database has to be formulated and indexed and how the answer has to be processed in order to guarantee smooth adjustment.

6We cannot and we do not want to respond to the problem of different subject cataloguing of one object in any database by adjusting its metadata. For various reasons the semantic and syntactic rules for each individual database may be very different but make sense. Instead, what we try to do to get optimal search results – in spite of the heterogeneity of the metadata – is to balance the semantical and syntactical differences of the content by means of linguistic analysis at indexing time.

7Therefore prometheus uses lingo6, an open source indexing system for research and education. The main functions of lingo are identification of (i.e. reduction to) basic word form by means of a simple suffix list, algorithmic decomposition, dictionary-based lexical synonymisation and identification of phrases, and generic identification of phrases or word sequences based on succession of word classes. Lingo knows two different kinds of dictionaries : dictionaries, which simply consist of word forms, the basic word form of a word and the appropriate word class and dictionaries, which contain synonyms without any morpho-syntactic information. These dictionaries include e.g. the English translation of German words.

Web application

8The technical basis of prometheus is the Web Application Framework Ruby on Rails with the search engine Ferret behind it.

9Besides the optimization of search results by balancing the semantical and syntactical differences of the content by means of linguistic analysis by indexing time, the user is also able to modify the search result’s retrieval-side by using special query syntax like phrase search, wildcards, fuzzy search or boosting or by indicating the relationships between the search terms with Boolean operators and, NOT and OR.

10The user can also restrict or specify the search pool by selecting individual databases or groups of databases. The databases are qualified by different criteria such as location, content focus and function (institutional database, museum database and research database).

11Regarding the search results the user has also different possibilities to arrange the images. First of all, the user is able to sort the results by criteria such as artist, title, location, credits or database, which facilitates the locating and grouping of relevant images. Additionally, the user may arrange the results individually. That means that s-he can choose between different amounts of records displayed or between two display modes : list or gallery. Hovering over the thumbnails activates/causes a slight zoom of the image (fig. 1).

Fig. 1 – Result list with display mode ‘gallery’ and slight zoom of the respective image.

12With a single click on the image the full record is shown with a medium sized image7 and all the information that is provided by the respective database (fig. 2). Additionally, similar images (based on the content of the records) are suggested on the bottom of the page.

Fig. 2 – Full view with a medium sized image and further information.

13Next to the image retrieval, prometheus offers the possibility to create personal collections (fig. 3) in order to compile images on a certain topic (i.e. for a class or paper).

Fig. 3 – Collection.

14The collections can be linked with keywords and edited to become presentations (fig. 4). The arrangement of the slotsand the number of images in one slot is flexible. Your presentation’s structure and optics remain flexible and basically up to you.

Fig. 4 – Présentation.

Prometheus2.0

15Referring to the Web 2.08 term, which encapsulates the idea of the proliferation of interconnectivity and interactivity of web-delivered content, prometheus wants to integrate collaborative and interactive elements to create a communication and interchange platform for research and education.

16To handle the problem of different image qualities the user is already able to rate the image’s quality in order to call the attention of the person in charge of the respective database. In addition to this, prometheus will also provide the opportunity to write a comment about the record data or the image to make aware of incorrect metadata or to initiate a research discussion. Furthermore, the user should be able to create his own profile, invite other users to join or to work on his collections or presentations or upload own images.

Continuity and financing

17Since 2004, the non-profit association prometheus – the distributed digital image archive for research and education e.V. “has guaranteed the long-term existence and further development of the former project”. The head office is situated in Cologne, at the institute of art history at the University of Cologne.

18Our financing relies on a combination of third-party-funds and license fees. The license fees are at present rather low compared to the ones demanded by similar archives.

19The licence fees are usually covered by the university libraries – as is the case with digital dictionaries and other research tools that are used by a broad range of academic disciplines. Campus and institutional fees enable free access for a considerably large group of users, among them students and learners of all kinds.

20For these kind of licenses prometheus cooperates with the centre of university libraries in Cologne, which manages the marketing of licences for us.

21Single fees can be acquired by persons, who are not a member of an institution with a license. Newly we support an online registration and the payment of the license via the e-payment service ClickandBuy.

Copyright and publication management

22Prometheus has always demonstrated a keen interest in being informed about copyright legislation, in giving advice to its partners on actions to take, and in finding solutions so that open access to cultural goods is guaranteed as a natural prerogative of research and education. Concerning the copyright of artworks and photographies, prometheus has contracted two types of cooperation :

• on the one hand, prometheus has an agreement with the collecting society “VG Bild-Kunst”. It effects the works of art of an artist up to 70 years after the demise of the artist (UrhG §64). According to this agreement, it is permitted that the images in question are made available through the various image databases cooperating in prometheus. This includes the permission to use these images world-wide as instruction materials by academic institutions and schools as well as for individual scientific purposes without paying a fee or obtaining a license ;
• on the other hand we were able to negotiate an exemplary agreement of cooperation with the commercial image archive “Bildarchiv Preußischer Kulturbesitz” (bpk) in Berlin. It effects the reproduction of a work of art up to 50 years after the creation of the photograph/slide, or 50 years after its first authorized publication. The agreement permits the use of all digital images that have been made available to prometheus by bpk, free of charge in non-profit, scientific publications with a circulation of less than 1 000 copies.

23These arrangements are models for future modes of copyright and publication management in order to facilitate the scientific use of images of fine art objects (fig. 5).

Fig. 5 – Result list with publication button and publication form.