The National Digital Library (NDL) aims to offer online, worldwide and free access to digitized manuscript and printed works – books, serials, iconography, cartography or music – held in the collections of the National Library of Portugal, the Évora Public Library and also, to a certain extent, the Ajuda Library, the former Portuguese Royal Library.
In this context, BND's main priority is to promote heritage collections, democratizing access to them by serving an increasingly vast community of users while contributing to preserve the original materials, especially the oldest, rarest or most fragile, as well as taking opportunities to digitize content for cultural or scientific projects, at a community, national or international level.
The resources made available by the NDL are mostly works in the public domain, that is, with no copyright restrictions, that can be freely used for any purpose, without the need for authorization. Additionally, NDL may include content that is still protected by copyright, in this case duly marked as such and available only on the National Library of Portugal internal network.
Access and functionalities
Access to the resources can be made by the NDL search system, through the National Library Online Catalog or by browsing the different collections, by type of document, subject, title, author or date of publication indexes. When consulting digital objects, NDL provides a set of functionalities such as selecting between different formats, downloading, sending by email, browsing tables of contents or keyword searching in documents with optical character recognition.
Content aggregation for international dissemination
NDL promotes the international dissemination of digital content from Portuguese libraries, through RNOD – the National Registry of Digital Objects, which aggregates and distributes metadata from more than 40 institutions to international portals such as Europeana, the Digital Library of Ibero-American Cultural Heritage, the Luso-Brazilian Digital Library, or the World Digital Library.
All NDL resources can be referenced through persistent identifiers which warrant the uniqueness and permanence of their web addresses, at the object level (e.g. a book), for each of the available formats (e.g. jpg, pdf, IIIF or HTML), as well as for each of each component parts (e.g. a page).
All NDL metadata, as well as RNOD metadata, are available as open data sets, in various formats (RDFXML, JSON and TURTLE), through the OPENDATA.bnportugal.pt portal, which allows their free reuse.
All NDL resources are provided with a rights’ status. Works already in the public domain are assigned the Public Domain mark and can be used freely. NDL metadata is released under a CC0 (Creative Commons CC0 1.0 Universal Public Domain Dedication) license, so it can be used and reused without restrictions.