Subtle Tricks

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United States’ Founding Father Benjamin Franklin was a true Renaissance man.

Known for inventing the lightning rod and bifocal eyeglasses, he also developed some of the earliest tricks to fight counterfeit paper money flooding the US colonies in the 18th century.

In 1731, Franklin won a contract to print £40,000 for the colony of Pennsylvania and came up with complex designs that made it harder for currency forgers to falsify.

Now, a new study showed that Franklin’s anti-counterfeit methods were more advanced and intricate than previously considered, the New York Times reported.

Scientists analyzed more than 600 pre-Federal American currencies using microscopy and spectroscopy techniques to analyze the paper on which the money was printed.

They discovered traces of mica – also known as muscovite – a group of silicate minerals that appear as small shiny flakes on the paper bills. Researchers observed that the mica found in bills from various colonies originated from the same geological source, indicating that a single paper mill might have produced the paper.

The presence of schist – a mineral containing mica – in the Philadelphia area suggests that Franklin or the printers associated with him obtained the material locally for their paper production.

The team also found evidence of graphite ink on the early currency. This puzzled them because the graphite was not easy to find and Franklin mainly used black ink from burned vegetable oils – known as lampblack – for printing jobs.

The differences in color between graphite and lampblack are also very subtle, which means that Franklin was possibly experimenting with different inks to fool counterfeiters.

The findings don’t specify whether the Founding Father’s methods were specifically aimed at fighting forgeries, but they do underscore his creativity.

The authors hope that future studies can reveal more about Franklin’s methods and other early American paper money.