“Virtual Unfolding” – Scientists Read 300-Year-Old Sealed Historic Letter Without Opening It

Unfolding Letterpacket DB-1627

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Computer-created unfolding animation of sealed letter DB-1538. In our paper we explain how “virtual unfolding” was utilized to check out the contents of sealed letterpackets from 17th-century Europe without physically opening them. Credit: Courtesy of the Unlocking History Research Group archive

History unfolds as an interdisciplinary research study group utilizes computational tools to analyze the contents of “locked” letters.

An global group of scholars has actually checked out an unopened letter from early contemporary Europe — without breaking its seal or harming it in any method — utilizing an automated computational flattening algorithm. The group, consisting of MIT Libraries and Computer Science and Artificial Intelligence Laboratory (CSAIL) scientists and an MIT trainee and alumna, released their findings on March 2, 2021, in a Nature Communications short article entitled, “Unlocking history through automated virtual unfolding of sealed documents imaged by X-ray microtomography.” 

The senders of these letters had actually closed them utilizing “letterlocking,” the historic procedure of folding and protecting a flat sheet of paper to become its own envelope. Jana Dambrogio, the Thomas F. Peterson Conservator at MIT Libraries, established letterlocking as a discipline with Daniel Starza Smith, a speaker in early contemporary English literature at King’s College London, and the Unlocking History research study group. Since the documents’ folds, tucks, and slits are themselves important proof for historians and conservators, having the ability to analyze the letters’ contents without irrevocably harming them is a significant development in the research study of historical files.

“Letterlocking was an everyday activity for centuries, across cultures, borders, and social classes,” describes Dambrogio. “It plays an integral role in the history of secrecy systems as the missing link between physical communications security techniques from the ancient world and modern digital cryptography. This research takes us right into the heart of a locked letter.”

Virtually Unfold an Unopened Letter

Using computational tools, a research study group had the ability to practically unfold an unopened letter from 1697. Credit: Courtesy of MIT Libraries

This development method was the outcome of a global and interdisciplinary cooperation in between conservators, historians, engineers, imaging professionals, and other scholars. “The power of collaboration is that we can combine our different interests and tools to solve bigger problems,” states Martin Demaine, artist-in-residence in MIT’s Department of Electrical Engineering and Computer Science (EECS) and a member of the research study group. 

The algorithm that makes the virtual unfolding possible was established by Amanda Ghassaei SM ’17 and Holly Jackson, an undergraduate trainee in electrical engineering and computer technology and an individual in MIT’s Undergraduate Research Opportunity Program (UROP), both operating at the Center for Bits and Atoms. The virtual unfolding code is freely offered on GitHub. 

“When we got back the first scans of the letter packets, we were instantly hooked,” states Ghassaei. “Sealed letters are very intriguing objects, and these examples are particularly interesting because of the special attention paid to securing them shut.”

Secrets exposed

“We’re X-raying history,” states staff member David Mills, X-ray microtomography centers supervisor at Queen Mary University of London. Mills, together with Graham Davis, teacher of 3D X-ray imaging at Queen Mary, utilized makers specifically created for usage in dentistry to scan unopened “locked” letters from the 17th century. This led to high-resolution volumetric scans, produced by high-contrast dead time combination X-ray microtomography.

“Who would have thought that a scanner designed to look at teeth would take us so far?” states Davis.

Computational flattening algorithms were then used to the scans of the letters. This has actually been done effectively prior to with scrolls, books, and files with a couple of folds. The complex folding setups of the “locked” letters, nevertheless, presented special technical obstacles.

Jacques Sennacques Letter

Researchers had the ability to check out the contents of a letter from Jacques Sennacques to his cousin Pierre Le Pers, a French merchant in The Hague. Credit: MIT

“The algorithm ends up doing an impressive job at separating the layers of paper, despite their extreme thinness and tiny gaps between them, sometimes less than the resolution of the scan,” states Erik Demaine, teacher of computer technology at MIT and a professional in computational origami. “We weren’t sure it would be possible.”

The group’s method makes use of a totally 3D geometric analysis that needs no previous info about the number or kinds of folds or letters in a letter package. The virtual unfolding produces 2D and 3D restorations of the letters in both folded and flat states, plus pictures of the letters’ composing surface areas and crease patterns. 

“One of coolest technical contributions of the work is a technique that explores the folded and flattened representations of a letter simultaneously,” states Holly Jackson. “Our new technology enables conservators to preserve a letter’s internal engineering, while still giving historians insight into the lives of the senders and recipients.”

This virtual unfolding method was utilized to expose the contents of a letter dated July 31, 1697. It consists of a demand from Jacques Sennacques to his cousin Pierre Le Pers, a French merchant in The Hague, for a qualified copy of a death notification of one Daniel Le Pers. The letter originates from the Brienne Collection, a European postmaster’s trunk preserving 300-year-old undelivered mail, which has actually supplied an uncommon chance for scientists to study sealed locked letters. 

“The trunk is a unique time capsule,” states David van der Linden, assistant teacher in early contemporary history, Radboud University Nijmegen. “It preserves precious insights into the lives of thousands of people from all levels of society, including itinerant musicians, diplomats, and religious refugees. As historians, we regularly explore the lives of people who lived in the past, but to read an intimate story that has never seen the light of day — and never even reached its recipient — is truly extraordinary.”

Advancing a brand-new field

In the Nature Communications short article, the group likewise reveals the very first system of letterlocking strategies. After studying 250,000 historic letters, they designed a chart of classifications and formats that appoints letter examples a security rating. Understanding these security strategies of historic correspondence implies archival collections can be saved in manner ins which secure little however essential product information, such as slits, locks, and creases. 

“Sometimes the past resists scrutiny,” describes Daniel Starza Smith. “We could simply have cut these letters open, but instead we took the time to study them for their hidden, secret, and inaccessible qualities. We’ve learned that letters can be a lot more revealing when they are left unopened.”

The research study group wishes to make a research study collection of letterlocking examples offered to scholars and trainees from a series of disciplines. The virtual unfolding algorithm might likewise have broad applications: Because it can deal with flat, curved, and greatly folded products, it can be utilized on lots of kinds of historic texts, consisting of letters, scrolls, and books. 

“What we have achieved is more than simply opening the unopenable, and reading the unreadable,” states Nadine Akkerman, reader in early contemporary English literature at Leiden University. “We have shown how truly interdisciplinary work breaks down boundaries to investigate what neither humanities nor the sciences can hope to understand alone.” 

Computational tools assure to speed up research study on letterlocking along with expose brand-new historic proof. Thanks to this research study, includes Rebekah Ahrendt, associate teacher of musicology at Utrecht University, “we can now imagine new affective histories that physically connect the past and the present, the human and the nonhuman, the tangible and the digital.”

For more on this research study, read Secrets of Unopened Letter From Renaissance Europe Revealed – Without Breaking Its Seal or Damaging It.

The research study group consists of Jana Dambrogio, Thomas F. Peterson Conservator, MIT Libraries; Amanda Ghassaei, research study engineer at Adobe Research; Daniel Starza Smith, speaker in early contemporary English literature at King’s College London; Holly Jackson, undergraduate trainee at MIT; Erik Demaine, teacher in EECS; Martin Demaine, robotics engineer in CSAIL and Angelika and Barton Weller Artist-in-Residence in EECS; Graham Davis and David Mills, Queen Mary University of London’s Institute of Dentistry; Rebekah Ahrendt, associate teacher of musicology at Utrecht University; Nadine Akkerman, reader in early contemporary English literature at Leiden University; and David van der Linden, assistant teacher in early contemporary history at Radboud University Nijmegen.

This research study was supported in part by grants from the Seaver Foundation, the Delmas Foundation, the British Academy, and the Nederlandse Organisatie voor Wetenschappelijk Onderzoek.

Reference: “Unlocking history through automated virtual unfolding of sealed documents imaged by X-ray microtomography” by Jana Dambrogio, Amanda Ghassaei, Daniel Starza Smith, Holly Jackson, Martin L. Demaine, Graham Davis, David Mills, Rebekah Ahrendt, Nadine Akkerman, David van der Linden and Erik D. Demaine, 2 March 2021, Nature Communications.
DOI: 10.1038/s41467-021-21326-w

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