Wikipedia:GLAM/National Library and National Archives of the Netherlands/Data/OpenDataKB/WILC

=Watermarks in Incunabula printed in the Low Countries (open dataset)=

Over 16,000 watermarks from books printed between 1450 and 1501 in the Low Countries (today the Netherlands and Belgium)

Contents of the set
With the dataset Watermarks in Incunabula printed in the Low Countries, the Koninklijke Bibliotheek offers access to 16,071 watermarks from books printed between 1450 and 1501 (so-called incunabula) in the Low Countries (today the Netherlands and Belgium).

The WILC set comprises 16,071 images of watermarks taken from the 2,229 incunabula editions preserved in 14,300 copies worldwide (many of them in more than one copy). The set includes watermarks from books held in libraries, archives and museums all over the world. The strength of the set is the huge quantity of illustrations, all of which have detailed descriptive metadata. The addition of four geographical coordinates (longitude and latitude of the places of manufacture and preservation) allows the set to be used in various ways.

The KB offers this as open (cultural) data: there is a CC0 license for the metadata, there is also a CC0 license for the individual objects (images of watermarks).

About watermarks
Watermarks were created during the manufacture of the paper on which books were printed. Paper pulp was scooped up by hand in a mould, a wooden frame with a mesh of thick and thin copper wires, which incorporated the watermark as a sort of factory logo. The paper is a little thinner where it rested on the wires that make up the watermark. Watermarks can be used to discover when and where the paper was made as each region and/or paper-mill used its own designs and the watermarks changed over time. Some watermarks designs are very common (for example the bull’s head or a hand). Therefore details of secondary features (such as chain lines and density) have been added to distinguish between watermarks that look very similar.

Watermarks can be seen by holding the paper up to the light. Images of them can be made by making the relief in the paper visible with a rubbing (like you used to make of pennies) or by radiography or photography. In WILC most images are rubbings (11,739) and radiographs (4,323).

Use of watermarks
Watermarks are used to locate anonymous paper objects. One can also date an undated paper object or, along with other techniques, establish a place of manufacture by comparing the watermark with objects whose date or source is known. For example, so far over 3,400 watermarks in 1,200 undated books have been dated. Not only books but also fifteenth century prints can be specified further.

Watermarks website
The KB has built watermark.kb.nl on which this material can be searched and which gives more help and background information on the material. Please contact the Koninklijke Bibliotheek for more specific information.

Files
The following files are available for the watermarks in the WILC set:
 * an image of the watermark (JPG), usually about 400 x 600 pixels (exact dimensions vary from scan to scan);
 * descriptive metadata (Dublin Core in XML) with permanent links to the above images.

The metadata and digital objects in the set are a total of 1,7 GB.

Technology
Technical explanations and examples of the are available in the comprehensive technical explanation (PDF, presently only in Dutch) on the set.
 * descriptive metadata (Dublin Core),
 * images (JPG)
 * metadata harvesting API, based on OAI-PMH
 * search API, based on SRU

Terms and conditions for reuse & credits

 * The KB has waived its copyright on the metadata for this set, which, therefore, has a CC0-license.
 * The KB has also waived its copyright to the objects (images of watermarks) in the WILC set, which therefore also have CC0-licenses. This means that there are no copyright restrictions on reproducing, publishing, processing or sharing these illustrations.

Although there is no requirement to credit the source when using the set, the KB would be grateful for this. Please use the following text:

National Library of the Netherlands, The Hague. Source: watermark.kb.nl - [link to object].

The KB asks anyone who uses the digital watermarks in this set to respect the Europeana Usage Guide for public domain works (PDF).

Contact & feedback
We are very interested in who uses the data and for what purpose, so please send an email to dataservices@undefinedkb.nl with your contact details and a brief description of what you use the data for. Feedback on our data and APIs is of course also very welcome. The information you provide also lets us notify you of developments such as changes in the datasets or the release of new datasets.

The KB will of course treat your contact information with care.