Our paper conservator has been in the darkroom capturing images of watermarks from some of our Old Master prints. The prints, created in the 15^th and 16^th centuries in Europe, were made on handmade papers that were made on wire molds.  Images of the wires can be seen when the papers are viewed in transmitted light, when the paper is viewed on a lightbox and the light is transmitted through the paper.  The watermarks are created by designs sewn with wire onto the wire papermaking screens.  They can help identify where and when the papers were made and can even help determine if the prints were made during the artist’s lifetime.  Some of the paper mills had identifiable watermarks, but many are not easy to connect to a specific mill.

The printed images can obscure the watermarks, so simply looking at the prints on a light box does not always give researchers the best picture.  Shown here are images of a print viewed on a light box and an image of the same print made with Beta radiography.  Similar to an X-radiograph, a Beta-radiograph film is created by exposing the print and film to low energy radiation, then processing the film in a darkroom.  Only the darkest black ink printing shows up, as faint white lines, allowing the watermarks to be fully visible.  In this example, the Beta-radiograph clearly shows a watermark in the center of the sheet, a head in profile and a star.  Perhaps this will lead to an identification of the paper mill by art historical researchers.