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Benjamin Franklin was so busy as an inventor, publisher, scientist, diplomat and U.S. founding father that it’s easy to lose track of his accomplishments.

So add one more to the roster: his early work in printing colonial paper currency designed to counter a constant threat of counterfeiting.

Franklin was an early innovator of printing techniques that used colored threads, watermarks and imprints of natural objects such as leaves to make it far harder for others to create knockoffs of his paper bills. A team at the University of Notre Dame has shed new light on his methods using advanced scanning techniques that reveal some of Franklin’s methods in greater detail – along the way, also providing one more reason Franklin appears on the $100 bill.

Benjamin Franklin was so busy as an inventor, publisher, scientist, diplomat and U.S. founding father that it’s easy to lose track of his accomplishments.

So add one more to the roster: his early work in printing colonial paper currency designed to counter a constant threat of counterfeiting.

Franklin was an early innovator of printing techniques that used colored threads, watermarks and imprints of natural objects such as leaves to make it far harder for others to create knockoffs of his paper bills. A team at the University of Notre Dame has shed new light on his methods using advanced scanning techniques that reveal some of Franklin’s methods in greater detail – along the way, also providing one more reason Franklin appears on the $100 bill.

The Notre Dame team also learned that Franklin developed his own graphite-based ink at a time when competing printers were mostly using inks derived from “boneblack,” a charcoal-like substance produced by heating animal bones to high temperatures in a kiln that limited the flow of oxygen. The significance of Franklin’s graphite-based ink isn’t clear and needs further study.

Later, though, the Revolutionary War brought on such a surge of counterfeiting – much of it, apparently, courtesy of the British Army – that the subsequent U.S. government shunned paper bills for decades in favor of coinage. It didn’t reconsider until the onset of the Civil War in 1861, when the federal government first authorized the printing of dollar bills called “greenbacks.”

Among the features in those U.S. banknotes were, of course, colored threads. These remain in use today, albeit in a more modern form. Today’s U.S. currency, for instance, features an embedded “security thread” in bills denominated $5 or more, although it’s now a thin vertical band that fluoresces under ultraviolet light.