Benjamin Franklin may be best known as the inventor of bifocals and the lightning rod, but a team of researchers at the University of Notre Dame suggests he should also be known for his innovative ways of making (literal) money.
During his career, Franklin printed nearly 2,500,000 bills for the American Colonies using what researchers have identified as the most original techniques, according to a study published this week in Proceedings of the National Academy of Sciences.
The research team, led by Khachatur Manukyan, an associate research professor in the Department of Physics and Astronomy, spent the past seven years analyzing a trove of nearly 600 notes from the colonial period, which is part of an extensive collection held by the Hesburgh Rare Books and Special Collections Libraries. Colonial notes span an 80-year period and include notes printed by Franklin’s network of printing shops and other printers, as well as a series of counterfeit notes.
Manukyan explained that the effort to print money for the new Colonial monetary system was important to Franklin not only as a printer but also as a statesman.
“Benjamin Franklin saw that the financial independence of the Colonies was necessary for their political independence. Most of the silver and gold coins brought into the British American colonies were quickly exhausted to pay for manufactured goods. which was imported from abroad, leaving the Colonies without an adequate supply of money to expand their economy,” said Manukyan.
However, one major problem hinders efforts to print paper money: counterfeiting. When Franklin opened his printing house in 1728, paper money was a new concept. Unlike gold and silver, paper money’s lack of intrinsic value means it is always at risk of depreciation. There were no standardized bills during the Colonial period, which left an opportunity for counterfeiters to pass off fake bills as genuine. In response, Franklin worked to embed a set of security features that made his bills stand out.
“To maintain the authenticity of the notes, Franklin had to stay one step ahead of counterfeiters,” Manukyan said. “But the ledger in which we know he recorded these printing decisions and methods has been lost to history. Using physics techniques, we were able to restore, in part, some of what the record shows.”
Manukyan and his team used cutting-edge spectroscopic and imaging instruments located at the Nuclear Science Laboratory and four Notre Dame research core facilities: the Center for Environmental Science and Technology, the Integrated Imaging Facility, the Materials Characterization Facility and the Molecular Structure Facility. The tools enabled them to see more closely than ever before at the inks, paper and fibers that made Franklin’s bills unique and difficult to copy.
One of the most unusual features they found were Franklin’s pigments. Manukyan and his team determined the chemical elements used in each item in the Notre Dame collection of Colonial notes. The fakes, they found, had unusually high amounts of calcium and phosphorus, but these elements were only found in traces of real bills.
Their analyzes revealed that although Franklin used (and sold) “lamp black,” a pigment made by burning vegetable oils, for most printing, the printed money of Franklin used a special black dye made from graphite found in the rock. This pigment also differs from the “black bone” made from burnt bone, which was favored by counterfeiters and outside Franklin’s network of printing houses.
Another of Franklin’s innovations was in the paper itself. The invention of attaching tiny pulp fibers to paper—seen as the pigmented squiggles inside paper money—is usually credited to paper manufacturer Zenas Marshall Crane, who introduced the practice in 1844. But Manukyan and his team found evidence that Franklin included colored silks earlier in his paper.
The team also discovered that the notes printed on Franklin’s network had a different appearance due to the addition of a translucent material they identified as muscovite. The team determined that Franklin began adding muscovite to his papers and the size of these muscovite crystals on his paper increased over time. The team speculates that Franklin initially began adding muscovite to make the printed notes stronger but continued to add it when it proved to be a helpful deterrent to counterfeiters.
Manukyan said it is unusual for a physics lab to work with rare and archival materials, and this poses special challenges.
“Few scientists are interested in working with materials like this. In some cases, these charges are one-of-a-kind. They must be handled with extreme care, and they cannot be damaged. That constraints that would put many physicists off a project like this,” he said.
But for him, the project is a testament to the value of interdisciplinary work.
“We are fortunate to have student researchers on this project with interests in physics as well as art history and conservation. And the core research facilities as well as the Rare Books and Special Collections team are exceptional partners in research. collaboration across disciplines, our discoveries would not have been possible.”
Manukyan, Khachatur, Multiscale analysis of Benjamin Franklin’s innovations in American paper money, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2301856120. doi.org/10.1073/pnas.2301856120
Provided by the University of Notre Dame
Citation: All about the Benjamins: Researchers decipher the secrets of Benjamin Franklin’s paper money (2023, July 17) retrieved 18 July 2023 from https://phys.org/news/2023-07-benjamins -decipher-secrets-benjamin-franklin. html
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