Innocuously couriered across the globe in fireproof bags, priceless 15th-century documents arrived in Menlo Park at SLAC National Accelerator Laboratory for an experiment on the earliest printing presses.
While scientists at SLAC typically look to the future and break new ground, this time they're looking approximately 600 years in the past at metal residue in documents created on printing presses in the east and west. Their goal: to discover whether or not the East Asian printing press and the European Gutenberg press were simply invented at the same time, or if ideas were shared across the world.
"That would be the million-dollar question, and it will require a lot of work, a lot of effort to shed some light on that question. But that's the question, which kind of gets us really excited," said Uwe Bergmann, a professor of Ultrafast X-Ray Science from the University of Wisconsin at Madison.
Bergmann believes the printing press to be one of the most revolutionary inventions of the second millennium, and the invention is often credited to the Gutenberg printing press in the 1400s which began by printing bibles for mass consumption. However, movable type printing presses in Asia actually appeared a couple of hundred years before Johannes Gutenberg's invention, but did not take off in the same way because materials were still restricted to the upper class.
To accomplish their mission, scientists at SLAC have several texts to analyze, including Korean Confucian texts, pages from the Gutenberg bible and a first-edition copy of the Canterbury Tales, among others. Documents in the experiment are coming from Stanford and Korea's archives, as well as some from private collectors.
The documents were accompanied on their flights, hidden in fire retardant luggage bags in an effort to seem as mundane as any other piece of baggage carted through an airport.
Using an incredibly fine and high-powered X-ray beam, SLAC scientists are able to analyze the elements through a method known as X-ray fluorescence. Atoms constantly have energy coming off of them, and with this technique the beam is able to alter the energy coming off of a single atom. By measuring those altered energy signals, scientists can trace the signature back to specific elements that are present.
Every inch of the document is analyzed, and every element found is reported back to researchers.
This strategy allows scientists at SLAC to create element maps of pages, uncovering evidence of several metals on one page and even a fingerprint.
According to Angelica Noh of UNESCO, researchers have not only found a fingerprint, but stains on the pages that could give perspective beyond just the movable typeface. Instead, this could illuminate small aspects of people's lives around 600 years ago.
After finding an unexpected amount of copper in a document, researchers have already had to start analyzing past printing in a new light.
"Now we kind of piece the puzzles together with people completely outside of the STEM field, historians or archivists, people who have collected like historical knowledge about what was going on, to try to figure out what is happening here," said Minhal Gardezi of the University of Wisconsin at Madison.
As of yet, there's no compelling evidence on whether or not the Gutenberg press was influenced by East Asian printing, but the project is only getting started and is expected to last for over six years.
Lead X-ray scientist Sam Webb is assisting the team with the help of an X-ray that he completely rewrote the software for during the COVID-19 pandemic. The beamline being used in the experiment can run 24 hours a day from his phone, taking data even when there are pandemic precautions in place.
"You can really kind of, like, look back into history with this and use our tools to look back at that way," Webb said. "It's a lot of fun to kind of think, you know, we can find things that are missing or learn how materials were made, you know, hundreds and thousands of years ago, and it's fun. (It has this) aspect of being fun as well as science"
Though a historic exercise, Webb said that the research also can be effective today. The elements used thousands of years ago are used in items today, such as batteries, and analyzing ancient chemical compounds can help understand the materials as they currently exist.
Beyond just analysis, the project has another goal: to prompt Paris's Bibliothèque Nationale de France to reveal Asia's first printed piece, Jikji. The French museum has only shown the document once, according to Noh.
When the project wraps in 2027, the team wants to have 44 exhibitions across the world, and Noh said that she's hoping if there's enough interest in the project, Jikji may be shown to the public once more.
"We can like apply a little bit of pressure so ... as people gauge their interest toward it, they would like to see the actual printed materials and hopefully it all can be shown to the world again," said Noh.
As much as scientists can hypothesize about what they may find, they're in uncharted waters with this method of analysis. According to Bergmann, they still could find completely unexpected metals or ratios that don't make sense, it's all a matter of what the element maps say.
"None of those objects, including that really very important Confucious book which was printed either slightly before Gutenberg or slightly after — we don't quite know yet — neither of them had ever been studied with such kind of a chemical analysis," Bergmann said. "So we are in completely new territory here."