A papermaker in Massachusetts named Zenas Marshall Crane is traditionally credited with being the first to include tiny fibers in the paper pulp used to print currency in 1844. But scientists at the University of Notre Dame have found evidence that Benjamin Franklin was incorporating colored fibers into his own printed currency much earlier, among other findings, according to a new paper published in the journal Proceedings of the National Academy of Sciences (PNAS). //

The first paper money appeared in 1690 when the Massachusetts Bay Colony printed paper currency to pay soldiers to fight campaigns against the French in Canada. The other colonies soon followed suit, although there was no uniform system of value for any of the currency. To combat the inevitable counterfeiters, government printers sometimes made indentations in the cut of the bill, which would be matched to government records to redeem the bills for coins. But this method wasn't ideal since paper currency was prone to damage.

By the time he was 23, Franklin was a successful newspaper editor and printer in Philadelphia, publishing The Pennsylvania Gazette and eventually becoming rich as the pseudonymous author of Poor Richard's Almanack. Franklin was a strong advocate of paper currency from the start. For instance, in 1736, he printed a new currency for New Jersey, a service he also provided for Pennsylvania and Delaware. And he designed the first currency of the Continental Congress in 1775, depicting 13 colonies as linked rings forming a circle, within which "We are one" was inscribed. (The reverse inscription read, "Mind your business," because Franklin had a bit of cheek.) //

The most recent discovery: very thin (between 100–300 microns) indigo-colored blue fibers and threads, found in Franklin's printed currency as early as 1739. Later bills that Franklin printed in the 1770s incorporated much larger threads and microfibers, measuring up to a few centimeters in length. Those blue fibers were not found in either the non-Franklin currency or the known counterfeits. “These [colored fiber] techniques have been used later on in printing federal dollars, and then other currencies all over the world,” Manukyan told New Scientist.

DOI: PNAS, 2023. 10.1073/pnas.2301856120 (About DOIs).