Centuries-old books, manuscripts, and printing plates often contain invisible etchings, mysterious letters—and even scribbles. A new technology that maps the surface of these objects brings them to light.
About 1,300 years ago, a woman bent over a precious book and etched some letters along with caricature-like drawings into the margin. She didn't use ink - she scratched them in so that they were almost invisible to the naked eye.
Until last year nobody knew they were there.
The8th century book– a copy of the Acts of the Apostles from the Christian New Testament – is now kept in the Bodleian Library in Oxford. Researchers have known for some time that the religious text likely belonged to a woman, but they weren't sure who.
2022 the researcher Jessica Hodgkinson at the University of Leicesterdecided to take a closer look, and was surprised to find a hidden etching on page 18, just below the Latin text.
Digitally highlighted it looked like this:
The hidden etching that sparked further investigation (Credit: Archiox/Bodleian Library)
The letters read: "EaDBURG BIREð CǷ….N", where the last word is incomplete. What could it mean?
Hodgkinson noted that the first symbol was a cross, followed by "Eadburg": almost certainly the name of the book's owner. Further analysis revealed that it had been intentionally scratched into four other pages with some sort of pen.
Not much is known about her, but Hodgkinson and colleagues suspect that Eadburg was a nun - the abbess of a religious community in Minster-in-Thanet, in the English county of Kent.
The following letters were a little more puzzling: Could it mean "bearsthe Cwerters" – the Old English word for "prison"? The Latin passage that accompanies it describes the imprisonment of the apostles, so Eadburg may have drawn a parallel to their own situation.
Even more fascinating, Hodgkinson and colleagues found drawings of small people on other sites. On one edge a square figure with outstretched arms - could it be a nun? (see below left above). In another, a person holds their hand to the face of a depressed attendant (bottom right). An 8th-century version of "speak with your hand"? Their meaning is a mystery.
Doodles in the Eadburg book: was it the owner or a mischievous child? It's a mystery (Credit: Archiox/Bodleian Library)
The marginalia in the Eadburg Book are not the only example of hidden writing and drawing that has been unearthed at Oxford in recent months. Hodgkinson was able to see Eadburg's etchings at the Bodleian Library thanks to new imaging technology that can map the physical texture and contours of a book page, manuscript, or the surface of other historical objects such as printing plates. Doing this down to the smallest detail reveals features that would otherwise be invisible to the eye or standard cameras.
"The surface itself carries a huge amount of information," explains Adam Lowe, founder of the Factum Foundation in Madrid, a non-profit organization that developed the technology for the Bodleian as part of the Archiox project (Analyzing and Recording Cultural Heritage in Oxford). . . "The more you can make that visible, the more really exciting discoveries will come out of it."
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Archiox researchers use two devices to create digital representations of pages and objects: the "Selene," which has four cameras that can detect differences in surface relief down to 25 microns (0.025 mm/0.001 in), and the " Lucida uses lasers and two tiny cameras to create 3D scans.
“Everything is measurable, this is not only an imaging tool but also a measurement tool. And that makes everything even more exciting,” says John Barrett, Senior Photographer at Bodleian and Chief Technical Officer at Archiox.
A close-up of this printing plate shows the texture that the technology can image and then digitize (Credit: Archiox/Bodleian Library)
In the basement of the Bodleian, the technology is now being used to create digital representations of various items in the library collection.
The Eadburg Book was not the only centuries-old document to reveal hidden etchings.
In this9th century manuscript, the Archiox researchers mapped a hunting scene scratched into the surface:
A hunting scene engraved in a 1,200-year-old manuscript (Credit: Archiox/Bodleian Library)
And then under the animals a name: the letters "RODA", which probably refer to the owner of the book. "It was never noticed," says Barrett.
Researchers did not see the name RODA until the manuscript was scanned (Image credit: Archiox/Bodleian Library)
Why would people have etched their names and added drawings like this almost invisibly?
With the names, it might have been easy to show ownership without scribbling a valuable religious text. “These manuscripts were considered sacred. And while you wanted to put your own stamp on them, you didn't want to be too obvious," explains Barrett.
As for the pictures, "I don't think it was necessarily just doodling for doodling's sake," he says. "Often these annotations, and certainly those I have included more recently, definitely have some relation to the text itself."
Some of the first items in the Bodleian collection to be scanned for the Archiox project wereCopperplates 200 to 300 years old- the Rawlinson Collection - selected by Alexandra Franklin, Coordinator of the Center for the Study of the Book, and Chiara Betti, PhD student at the University of London.
Here's an example where Archiox technology revealed a previously hidden etch on the back of a panel. On the obverse, it features an influential French cardinal, but when researchers looked at the reverse, there appeared to be weak staves:
To the naked eye the staves (left) were just visible and far less obvious than the cardinal on the front (right) (Source: Archiox/Bodleian Library)
... but when the 3D surface was mapped, they became much clearer (Credit: Archiox/Bodleian Library)
This revealed a piece of music and words underneath (Image credit: Archiox/Bodleian Library)
"It was probably inspired by Psalm 9 because the words seem to fit," says Barrett. The New King James Version of the Bible says in Psalm 9: “I will praise you, O Lord, with all my heart; I will tell of all your wonderful works; I will be happy and enjoy you; I will praise Your name, O Most High."
Why would anyone have done that? “The material [copper] itself was very valuable,” explains Barrett. "It could have been reused, or it would have just given the artist or engraver an opportunity to practice."
However, as he points out, there is no known printing of this music from disk, so the discovery added a new element to the historical record. "This was not marked in the catalog reference for this record. These are entirely new discoveries being made,” says Barrett. “I would say that probably a third of the plates I imaged for Archiox also had something on the back. Very often the designs are really beautiful or weird or mysterious.”
cards and artistry
Archiox technology has also provided new clues as to how objects were made, such ashistorically important mapunder.
"This is thatearliest recognizable map of the British Isles, dated to the 14th century," explains Barrett.
The Gough map of the island of Great Britain, with Scotland on the left and England and Wales on the right (Credit: Archiox/Bodleian Library)
The Archiox team's imaging of the surface revealed that "it's absolutely riddled with pinholes, over 2,000 of them...features like cathedrals and rivers and things were either pricked or nicked," says Barrett.
This suggests that some was copied, as map makers would have used pens to aid in the duplication, placing the original map on top of the duplication and using the sharp points to mark landmarks on the underlying material. "One might think that this early map was probably used to create other maps, but actually the opposite is true," he says.
Why so? Surface mapping revealed that "the pinholes don't go all the way through. So we can conclude that this was indeed copied from a precursor: an earlier map."
Here the pinholes are not clearly visible on the Gough map, just the detail of a town (Credit: Archiox/Bodleian Library)
...but when the surface was scanned, the pinholes were much more obvious (Credit: Archiox/Bodleian Library)
Finally, Archiox's scanning technology helps provide new insights into the artistry of objects. The Japanese woodcut below shows how. When the Archiox researchers scanned the surface, they found that the woodblock artist had added textures that they knew would have been invisible to the naked eye.
Look at the character's face and the bow around his head, both printed in the same color. See how there is a difference in texture?
A Japanese print and the scanned surface structure (Credit: Archiox/Bodleian Library)
"You're wondering why on earth did the printer bother to do this truly incredible embossing and embossing work if you can't appreciate it?" says beret. To change the way the light reflects off the finished print? Possibly. "I think the answer is that it was a labor of love. These things were made as perfect as possible. It gives you a new appreciation for the skills involved in making these things that you didn't really have before if you were just shooting them with traditional photography."
The BBC's Hannah Fisher recently presented the Archiox project's research for the Digital Planet radio programme.Listen to the episode on BBC Sounds from 11:20am.
Lowe suggests that through this new approach, thousands of new discoveries could be waiting to be made, hidden away in libraries and art collections. “People are beginning to realize that 'support information' changes our knowledge. There must be objects in libraries around the world that could benefit from this technology... it's about treating physical objects as evidence," he says. "A lot is known, but there's still a lot more to come, and I think that's an incredibly inspiring and exciting thought."
*Richard Fisher is senior journalist for BBC Future. Twitter:@rifish
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