Secrets of Money Printed by Benjamin Franklin Uncovered by Notre Dame Scientists

Analysis of a note printed by Benjamin FranklinPhoto byUniversity of Notre Dame

A recent study conducted by researchers from the University of Notre Dame sheds new light on Benjamin Franklin's lesser-known contribution to American history – his innovative methods of producing money during the Colonial period.

Published in the Proceedings of the National Academy of Sciences, the study led by Khachatur Manukyan, an associate research professor in the Department of Physics and Astronomy at Notre Dame, spanned seven years and analyzed nearly 600 notes from the era, including Franklin's own prints and counterfeit notes.

Benjamin Franklin saw that the Colonies’ financial independence was necessary for their political independence. Most of the silver and gold coins brought to the British American colonies were rapidly drained away to pay for manufactured goods imported from abroad, leaving the Colonies without sufficient monetary supply to expand their economy- Khachatur Manukyan, Associate Professor, Physics, Notre Dame.

However, counterfeiting posed a serious threat to the stability of the system.

To combat counterfeiters, Franklin introduced various security features that set his bills apart. The research team used cutting-edge spectroscopic and imaging instruments to gain insights into the inks, paper, and fibers used in Franklin's bills.

To maintain the notes’ dependability, Franklin had to stay a step ahead of counterfeiters,” said Manukyan. “But the ledger where we know he recorded these printing decisions and methods has been lost to history. Using the techniques of physics, we have been able to restore, in part, some of what that record would have shown.- Khachatur Manukyan, Associate Professor, Physics, Notre Dame.

They discovered Franklin's use of a unique black dye made from graphite found in rocks, distinguishing his prints from counterfeits that relied on other pigments. He also incorporated colored silks into his paper, a technique credited to a later paper manufacturer, and added muscovite, a translucent material, to enhance the bills' durability and deter counterfeiters.

Working with rare archival materials presented challenges, as the one-of-a-kind bills required extreme care to prevent damage. However, the interdisciplinary nature of the project, involving physics, history, and art conservation, proved successful.

The collaboration between researchers and the Rare Books and Special Collections team facilitated groundbreaking discoveries.