The printed word, a cornerstone of modern life, is a relatively recent development in human history. Despite the transformative impact of printing on our societies, much about its early history remains shrouded in mystery. A team of scientists recently employed powerful X-ray technology at SLAC National Accelerator Laboratory in California to delve into the production methods of some of the earliest known printed documents.
Early printing in Asia utilized woodblocks, a technique known as xylography, with documented examples dating back to 600 CE. Centuries later, Johannes Gutenberg revolutionized printing with movable type, a system involving a modified wine press and metal pieces, enabling the mass production of texts like his famous bibles.
Two key documents are at the heart of this research, conducted by a team of conservators, physicists, archivists, and imaging experts. The first is the “Noble” fragment, two pages from a Gutenberg Bible, disassembled and dispersed in the early 1920s by a New York antiquarian. With only 20 complete Gutenberg Bibles remaining today, these fragments hold significant historical value. The second document is a selection of pages from the 580-year-old Spring and Autumn Annals, a Korean text printed with movable type in 1442, predating Gutenberg’s work. This edition contains the writings of Confucius.
“The Chinese and Koreans undeniably invented movable type printing long before Gutenberg,” explains Uwe Bergmann, a physicist at the University of Wisconsin and a team member. “Our research seeks to understand the origins of printing. Did Gutenberg have knowledge of earlier Korean printing? Was his invention independent, or was it influenced by these prior innovations?”
Using SLAC’s synchrotron, a ring-shaped particle accelerator generating powerful X-rays, the team analyzed the chemical composition of over 20 Korean prints, the Gutenberg Bible fragments, and other historical texts, including a copy of William Caxton’s “Canterbury Tales.” Their investigation focuses on the ink chemistry and the type of metal used in the printing process.
“Our initial run was remarkably productive,” Bergmann reports. “We detected significant X-ray fluorescence signals from various elements in the inks and paper, exceeding our expectations.”
Several experimental methods can reveal different aspects of historical documents. Raman spectroscopy can detect faded ink, as demonstrated in recent research uncovering marginalia in an early version of the King Arthur legend. Multispectral imaging has unveiled words omitted by Thomas Jefferson from the Declaration of Independence.
Two preliminary X-ray fluorescence scans of Korean documents.Two preliminary X-ray fluorescence scans reveal the chemical composition of early Korean printed documents. (Image: Mike Toth/SLAC National Accelerator Laboratory)
This team utilizes X-rays because of their ability to reveal the chemical makeup of materials. In 2018, researchers at the University of Southern Denmark employed X-ray fluorescence to identify arsenic-based green ink in poisonous books within their collection.
“Having exhausted the possibilities of optical analysis, we are now using X-rays and X-ray fluorescence to obtain more fundamental information,” says Michael Toth, an X-ray imaging expert and team member. “This is a more complex process, as we are not searching for hidden text but for information beyond the text itself.”
This research team previously used X-ray fluorescence to examine the Archimedes Palimpsest in 2006 and a Syriac translation of Galen’s “On Simple Drugs” in 2018 and 2019. According to Toth, the recent work marks the first X-ray fluorescence analysis of a Gutenberg fragment in nearly four decades.
Handling these delicate and historically significant documents presents logistical challenges. Bergmann recounts how the Archimedes Palimpsest even had its own business class seat during transport for research. On-site, the documents are placed in custom sleeves for safe mounting in front of the synchrotron light source.
Two Korean documents and leaves of the Gutenberg Bible side-by-side at SLAC.Korean documents and Gutenberg Bible leaves undergo X-ray analysis at SLAC. (Photo: Jacqueline Ramseyer Orrell/SLAC National Accelerator Laboratory)
“As conservators, we strive to understand the material culture of the objects under our care,” explains Kristen St. John, a conservator at Stanford University Libraries and a member of the team overseeing the document scanning process. “Understanding the materials and methods used in their creation informs our preservation and accessibility efforts for our users.”
Supported by UNESCO, this project will publish its findings in the coming months and years. The researchers will convene in 2023 to discuss their initial results and plan to present a more comprehensive study on the early history of bookbinding and printing in 2027.
While the analysis and interpretation of the chemical maps will take time, this research promises to significantly advance our understanding of early printing processes.
