Inventor Benjamin Franklin devised unique measures to prevent the production and circulation of counterfeit money in America during the 18th century.
Benjamin Franklin is well-known for his inventions such as bifocal glasses and the lightning rod, but a team of researchers from the University of Notre Dame has pointed out that he also developed anti-counterfeiting technology. Throughout his career, Franklin printed nearly 2.5 million paper notes for the American colonies, employing unique techniques described in a study published on July 17 in the journal Proceedings of the National Academy of Sciences.
A researcher examines a bill under a spectroscopic device. (Photo: University of Notre Dame)
The research team, led by Khachatur Manukyan, an assistant professor in the Department of Physics and Astronomy, spent seven years analyzing nearly 600 colonial bills held in the Hesburgh Library’s Rare Books and Special Collections. These colonial notes circulated for 80 years, including money printed from Franklin’s printing network as well as a variety of counterfeit notes.
Manukyan explained that Franklin’s efforts to print money for the fledgling currency system in the colonies were crucial. “Benjamin Franklin recognized that financial independence was essential for the colonial states to achieve political independence. A large portion of gold and silver coins sent to the British colonies in America quickly depleted to pay for imported goods from abroad, leaving many colonial states with insufficient currency to expand their economies,” Manukyan stated.
However, a significant issue hindering the effort to print paper money was counterfeiting. When Franklin opened his printing shop in 1728, paper money was a relatively new concept. Unlike gold and silver coins, paper money lacked intrinsic value and was thus frequently at risk of devaluation. Without a standardized currency system during the colonial period, speculators had the opportunity to circulate counterfeit money. In response, Franklin developed a series of security features to identify genuine currency.
Manukyan and his colleagues utilized advanced spectroscopic equipment and imaging techniques at the Nuclear Science Laboratory and four core research facilities at the University of Notre Dame, including the Environmental Science and Engineering Center, the Integrated Imaging Facility, the Materials Characterization Facility, and the Molecular Structure Facility. These tools allowed them to examine closely the inks, paper, and fibers that made Franklin’s paper money unique and difficult to replicate.
One of the most notable features the research team discovered was Franklin’s ink. Manukyan and his colleagues identified the chemical elements used in each colonial bill in the collection. The counterfeit money they found contained high levels of calcium and phosphorus, but these elements were only detected in very small amounts in genuine notes.
The team’s analysis revealed that Franklin used black “lamp black”, a pigment produced by burning vegetable oil. Franklin’s printed money used a special black dye made from graphite, in contrast to the black “bone black” made from charred bones that counterfeiters preferred.
Another initiative by Franklin involved the printing paper. The innovation of mixing fine fibers into wood pulp to create paper, which is visible in the swirling patterns inside the paper money, was long believed to be the idea of paper maker Zenas Marshall Crane in 1844. However, Manukyan’s team found evidence that Franklin incorporated colored fibers into his printing paper much earlier.
The researchers also discovered that the paper printed by Franklin’s network had a distinctive shape due to the addition of a transparent material they identified as muscovite. According to them, Franklin began adding muscovite to the printing paper, and the size of the muscovite crystals increased over time. The research team speculated that Franklin initially added muscovite to make the printed money more durable but continued to add it as this feature proved useful in preventing counterfeiting.
