Of the 2000 fifteenth-century editions printed on paper in the Low Countries, only 800 are dated. One of the methods for narrowing down dates to a period of a few years is paper and watermark research. In the fifteenth century (and for the 300 years that followed) paper was handmade in moulds. Every mould was characterized by a small figure or letters of metal thread. In the paper sheet these show as thin lines. For a long time, the exact reproduction of watermarks was a problem. Nowadays, the best images can be made by electronradiography, a special technique using X-rays.
Watermarks in Incunabula printed in the Low Countries is a database of more than 16,000 images of watermarks derived from nearly all incunable editions printed in the Netherlands. Simple and advanced searches are possible, and result in images and descriptions of the watermarks.
Visit Watermarks in Incunabula printed in the Low Countries (WILC)