Barrett research with Libraries’ Special Collections reveals secrets of old paper

Research by a University of Iowa led team reveals new information about why paper made hundreds of years ago often holds up better over time than more modern paper.

Led by Timothy Barrett, director of papermaking facilities at the UI Center for the Book, the team analyzed 1,578 historical papers made between the 14th and the 19th centuries. Barrett and his colleagues devised methods to determine their chemical composition without requiring a sample to be destroyed in the process, which had limited past research. The results of this three-year project show that the oldest papers were often in the best condition, in part, Barrett says, due to high levels of gelatin and calcium.

“This is news to many of us in the fields of papermaking history and rare book and art conservation,” says Barrett. “The research results will impact the manufacture of modern paper intended for archival applications, and the care and conservation of historical works on paper.”

Barrett says one possible explanation for the higher quality of the paper in the older samples is that papermakers at the time were attempting to compete with parchment, a tough enduring material normally made from animal skins. In doing so, they made their papers thick and white and dipped the finished sheets into a dilute warm gelatin solution to toughen it.

“Calcium compounds were used in making parchment, and they were also used in making paper,” Barrett says. “Turns out they helped prevent the paper from becoming acidic, adding a lot to its longevity.”

Barrett acknowledges that some may wonder why research on paper longevity is worth doing today, when art or text on paper can be scanned at high resolution and viewed later on a computer. He notes that close analysis of the papers themselves can often shed new light on a particular historical episode or figure. For example, when letters from a particular writer are found on especially poor quality paper given the writer’s time and place, it may indicate something significant about the writer’s financial situation. When a book was printed on very high quality paper for its period and location, it may suggest something new about the publisher’s intended audience and marketing strategy.

“Both instances provide evidence wholly lacking in digital scans of the same pieces of paper,” Barrett says. “Paper does more than support words or images. It can bring alive its own moment in history or show us how to make longer lasting paper in the future.”

Even in a digital age, some materials will still be created and preserved on paper. For instance, Barrett and his UI papermaking team worked with National Archives staff in 2000 to produce special handmade paper that now sits beneath the Charters of Freedom at the Archives Rotunda in Washington D.C.

“The information lying dormant in paper in important books and works of art needs to be preserved for researchers in future generations to uncover and utilize,” Barrett says. “Just as important, paper originals — that can be read without hardware and software — will continue to be essential backups to digital scans long, long into the future.”

Barrett’s group included Mark Ormsby, physicist at the National Archives and Records Administration Research and Testing division; Joseph Lang, UI professor of statistics and actuarial science; Robert Shannon at Bruker Elemental; Irene Br├╝ckle, professor at the State Academy of Art and Design in Stuttgart, Germany; Michael Schilling and Joy Mazurek from the Getty Conservation Institute; Jennifer Wade at the National Science Foundation; and Jessica White, a UI graduate student who is now proprietor of the Heroes & Criminals Press.

The Institute for Museum and Library Services, the University of Iowa, and the Kress Foundation provided funding for the research. The UI Libraries is hosting the newly launched website http://paper.lib.uiowa.edu/ which details all the project goals, procedures and results. The UI Center for the Book is a part of the Graduate College.