Gravell, Thomas L.

Thomas Gravell, an authority on watermarks, died at age 91 in September 2004. A resident of Wilmington, Delaware, Gravel retired from E.I. duPont de Nemours and Company in 1975 after 34 years of service. He became an expert on watermarks after devising an inexpensive means of reproducing watermarks and co-authoring two books on the subject. Gravell’s interest in watermarks began with the watermarks from his stamp collection and later expanded to include identifying and reproducing watermarks in paper that was made in the United States and Europe prior to 1830. At the time Gravell began his research in 1970, there were two methods of reproducing watermarks. The first, tracing, was inexpensive yet failed to produce exact copies. The second, beta-radiography, was far more accurate, but was both time-consuming and expensive. Unhappy with these methods, Gravell learned that the Du Pont Company had just introduced Dylux 503, a photosensitive, instant image proof paper. Using this paper, he devised a new method for reproducing watermarks that proved to be inexpensive, accurate, and fast. Gravell placed the watermark on top of flourescent lamps and covered it with Dylux paper. Because the watermark was thinner than the rest of the paper, the flourescent light passed through the watermark with more intensity. The Dylux paper was then exposed to ultraviolet light which turned the watermark white and the unexposed area blue. The entire process could take as little as five minutes. Using his new Dylux method to reproduce watermarks, Gravell’s second career was underway. He duplicated watermarks from manuscript collections in Delaware at the Henry Francis du Pont Winterthur Museum, the Eleutherian Mills Historical Library, the Historical Society of Delaware, and Special Collections at the University of Delaware Library. He also collected watermarks from the American Antiquarian Society, the Huntingdon County Historical Society, the Folger Shakespeare Library, and the Library of Congress. In addition to identifying and reproducing watermarks, Gravell has also done research on papermaking, papermakers, and paper mills. His publications include: “Reproducing Watermarks for Study,” Proceedings of the American Antiquarian Society , Oct., 1972.; “A New Method of Reproducing Watermarks for Study,” Restaurator , 1975.; A Catalogue of American Watermarks, 1690–1835 (1979), with George Miller. New York: Garland Pub., 1979.; A Catalogue of Foreign Watermarks Found on Paper Used in America, 1700–1835 (1983), with George Miller. New York : Garland Pub., 1983.

“The Wizard of Watermarks,” Du Pont Magazine (Jan./Feb. 1990) 84:1, pp. 4-6. Thomas Gravell and George Miller. A Catalogue of American Watermarks, 1690–1835. New York: Garland, 1979.