Can a Particle Accelerator Trace the Origins of Printing?

There is a popular saying in Cheongju, South Korea, that “anyone who does not know Jikji is a foreign spy. ” The word appears on every street sign, and has been appended to the names of cafes, bookstores, and delis. For a few years, the local soccer team rebranded as Jikji FC.

“It’s literally everywhere. I’m not kidding,” says Angelica Noh, who recently moved to the city from Seoul. Noh learned the word in elementary school, “like everyone in Korea,” she says.

Jikji is the name of a book, a collection of Confucian teachings, that was printed by a group of monks in a temple in Cheongju in 1377. And though few outside of Korea know it, that date is significant: Jikji is the world’s oldest surviving book printed with movable metal type, predating the earliest Gutenberg Bible by 78 years. Noh, a program specialist at UNESCO, was describing her adopted city as she stood inside the Stanford Linear Accelerator Laboratory, or SLAC, in Menlo Park, California.

She had arrived that week from Korea with a collection of slightly newer documents in her luggage. Along with a set of European texts, they were there to be analyzed with the help of a synchrotron, a type of particle accelerator. As electrons whirl around the circular structure, they cast off X-rays that fly into small, sealed laboratory chambers where scientists conduct experiments.

At that moment, this particular chamber was host to an unusual tableau: an original copy of the Gutenberg Bible, produced in Germany in the 1450s, carefully strung up by its outer cover so that it dangled in front of the X-ray beams. For the next five hours, the Bible would make slow undulations from side to side, its pages scanned in sections about 60 microns wide, or just more than half the width of a strand of hair. The point of this exercise was a form of elemental sleuthing.

When high-energy X-rays hit an object, like the Bible, excited atoms in the ink and paper start firing off electrons, producing fluorescent light. Depending on what type of element has been hit—whether it’s chlorine, or copper, or tin—this light is emitted with a particular amount of energy, which can be imaged, producing a map of the elements that are found on the page. With those images, the researchers hoped to compare the printing traditions of Asia and Europe.

In the lab that day, they were racing to image dozens of documents produced on opposite sides of the world but at roughly the same time, mostly within the 15th century. The Korean artifacts, an array of mostly Confucian texts, represented hundreds of years of movable type printing in Asia, which dates back to at least the 11th century, while the European ones, which also included a first edition of The Canterbury Tales and a second copy of the Gutenberg, represented the very birth of the tradition there. They were created at a time when the cultures of the two continents had drifted closer together, but the historical record is virtually silent on what technological links, if any, existed between them.

Perhaps, the researchers hoped, a closer look at the objects would offer molecular clues about the processes that produced the documents, and their potential similarities. “Is there a bridge?” asks Randy Silverman, a preservation librarian at the University of Utah who is coleading the Jikji -Gutenberg project. “Is there a path for the technology to have been communicated through trade routes? Did Gutenberg see something from Asia and say, ‘Why not here?’” But while the Stanford researchers have a Gutenberg Bible, they don’t have Jikji itself.

It is in France, where it has not been seen by the public for about 50 years. In 1887, it was purchased by a French ambassador to Korea, then sold to a collector and eventually donated to France’s national library. Since then, the Korean government has repeatedly demanded its return—and once got close, when a trade was briefly floated as a part of a deal involving high-speed rail technology.

But the librarians protested, and the demand has softened to a loan—or even a public display in Paris. “We don’t even think about gaining access to Jikji for ourselves right now. We just want it to be shown to the public first,” says Seung-Cheol Lee, a research director at UNESCO and the project’s other director.

So in the meantime, the documents he and Noh had brought from Korea would have to suffice. The printing press is often thought of as a singular invention—a guy in Mainz, Germany, comes up with a breakthrough that sparks the printing revolution and gives rise to the European Enlightenment and, well, modernity. But scholars have long debated how German printing developed.

Was it an independent innovation, born out of the development of European metalworking? Or was a craft that was passed through trading routes and across empires, whether directly or through a more informal spread of ideas? Other Asian innovations, like paper and gunpowder, have a clear record of dissemination to Europe, with artifacts and record-keeping that trace their travel westward along routes of trade and conquest. Printing doesn’t have that kind of paper trail, says Valerie Hansen, a professor of Chinese history at Yale University. There is no evidence that European printers saw the fruits of Asian printing, like money or pamphlets, and then tried to reverse engineer the processes that made them—though it’s plausible, given increasing contact between east and west in the 13th and 14th centuries.

A close look at both printing technologies has also revealed more differences than similarities: different inks (oil-based in Europe versus water-based in Asia) and different processes to create the metal types, which stamp ink into the page. In the 14th century, when Jikji was printed, Korean printers were widely using a method called sandcasting to produce types, which involves filling molds lined with compressed sand. To create their movable type, Europeans swapped sand for metal.

One of the benefits was that, unlike sand, these metal molds could be reused, allowing the types for individual letters to be mass produced. This is one factor thought to have helped the printing press spread so quickly in Europe. That innovation has long been traced back to Gutenberg’s workshop.

But in the early 2000s, in front of a packed house at a literary club in New York City, a pair of Princeton researchers outlined a startling theory : Perhaps Gutenberg’s creations represented less of a singular technological triumph than people had previously thought. Their analysis focused on subtle imperfections in the text. If a metal mold had been used to create the types, each letter—say, all the letter a ’s on a page—should be the same.

But a mathematical analysis revealed that there were differences in the letters. The researchers hypothesized that the patterns were more in line with sandcasting. Not everyone agrees with that interpretation, but since then, there has been more evidence in its favor.

As a way of kicking off a deeper study of Gutenberg’s methods for the Jikji project, Silverman asked Jonathan Thornton, a retired librarian and craftsman at the State University of New York at Buffalo, to see whether he could recreate the typographic flaws using sandcasting techniques in his own workshop. Lo and behold, it appeared to work. The use of sandcasting doesn’t definitively link the two traditions—various forms of the technique were common in both Asia and Europe at the time—but it’s yet another example of how the two traditions are slightly closer than people think.

It would so also mean that the metal mold, with its regular, replicable type, likely came later, and suggest that the printing press was a more gradual development than a sudden arrival on the scene. “It turns out we don’t know very much about Gutenberg, this guy who we’ve all said modernity hinges on,” Silverman says. Mining objects with X-rays isn’t a new method.

A Gutenberg Bible had been analyzed in the 1980s at a much less powerful particle accelerator at the University of California, Davis. But the Stanford synchrotron is far more sensitive, expanding the range of the elements and the level of detail it can see, says Mike Toth, an imaging expert who frequently works with ancient objects. These X-rays are often used to explore what can’t be seen—such as in cases where a document is rolled up and can’t be unfurled , or to check whether a hidden painting was covered up by another artist to save canvas.

If it’s known that a covered-up ink or pigment is made of, say, iron, and the ink that covers it isn’t, the X-ray imaging can reveal it by isolating that element. In this case, the research team could read the words on the page with their own eyes. But they weren’t sure exactly what they were looking for as they compared the scanned texts.

(Multiple scholars happily admitted it was “a fishing expedition. ”) There were certain givens. They expected to see lead in the European inks, for example, and copper in the Asian ones, based on surviving descriptions and artifacts.

Mercury appears in the Confucian texts where the monks went back to highlight an important passage in red ink. But they also hoped to see something new. One reason that Gutenberg’s history has so many unknowns is that the types that were used to create the first printed Bible have been lost.

But what if they left an elemental imprint on the pages? Perhaps when they were pressed on the paper, along with the slightly caustic ink, some atomic evidence that would reveal what they were made of was rubbed off too. Toth compares this to forensic imaging: looking for clues in something that wasn’t meant to be left behind. The researchers didn’t have much time to do it.

They were in a race against limited “beam time,” scanning the dozens of documents before the SLAC facilities shut down for a few weeks of scheduled summer maintenance. The scanning was thus a 24-hour affair that week in late July, with scientists working in shifts at the lab and gathering the next morning on Zoom with scholars and historians around the world to discuss what they had found and what data they should gather next. For each document, they would create an elemental profile using the X-ray fluorescence, followed in some cases by a second X-ray scan that measured the amount of energy absorbed by the atoms.

This can help decipher the form in which an element occurs—for example, if an iron atom is bonded with oxygen to form an iron oxide, that might indicate it is from an ink sample. Within the next few years, they plan to publish that data and launch a touring exhibit of their findings and interpretations from scholars. But they did unearth one early surprise: an unexpected abundance of copper on the pages of both the Korean texts and the Bible.

The next day, on Zoom, the scholars began trading theories. Perhaps it was an unknown ingredient in the ink? Or had they made a discovery about the type that Gutenberg used? Or maybe it had nothing to do with the printing at all; perhaps 15th century printers on both continents just used a copper cauldron to mix their inks. “People don’t automatically understand what any of it means,” Silverman says.

It’s unlikely that the project will uncover any specific links between the Korean and European texts. “Did movable type move from Korea and Mainz? That’s too specific a question to answer,” says Hansen. But there’s value, she says, in highlighting the complexities and overlaps between the traditions.

“There are multiple paths to the modern world, and so much of our energy has been looking at the European path,” she says. Perhaps it’s more interesting, she adds, to ask why one culture turned more quickly to mass printing than the other. Both converged on similar technical answers to the problem of spreading information.

But in Europe, the politics of the early Renaissance and the Protestant Reformation may have had as much to do with the demand as innovation—the right technology at the right time. And there are practical reasons to consider, too: The Latin alphabet contains only 26 letters, which were relatively simple to mass produce as type pieces. Chinese script, which was then used in Korea, has thousands of characters.

The researchers also hope that the project will draw attention to Jijki . They hope the French National Library will agree to show the book as part of a series of exhibits that will show off the results of the research at SLAC. (Representatives of the library did not respond to a request for comment.

) The point, according to Silverman, isn’t to hold up Jikji as a singular achievement, or as a competitor to Gutenberg, but as a representative of one of the many paths that took us to the modern world. “We’re trying to show that there’s no such thing as a monopoly on scientific knowledge,” he says. .