Isolating Watermarks in Antique Paper
We are currently designing software and associated optimal conditions of capture to isolate images of watermarks and internal paper structure in archival paper. The method uses visible light photographs and requires only a camera, a computer, and a light table to implement. We hope to produce images that rival those produced with the standard watermark imaging technique of beta-radiography in terms of efficiency of capture and accuracy.
Out technique uses photographs taken in two lighting conditions, one with a light table beneath the paper being imaged and the other in ambient lighting. The software in development uses the ambient light image, in which only features on the surface are visible, to suppress those features in the transmitted light image, which contains both surface information and subtle changes in brightness due to shifts in paper density. In the resulting
The internal structure of paper including laid lines, chain lines, watermarks and any production related changes in density are diagnostic of the conditions, date, and location of a sheet of paper’s production. In particular, our method seeks to access the information contained in
