45th Annual Meeting — Research and Technical Studies Session, June 1, 2017 — “Revealing the text and folds in 17th-century locked letters” presented by Jana Dambrogio

The final talk of the June 1st RATS session was by Jana Dambrogio, Thomas F. Peterson (1957) Conservator, MIT Libraries, Curation & Preservation Services. Jana has been working for several years on the subject of “letterlocking,” the many techniques by which a letter can be folded to form its own envelope. Some of these letters are folded very simply while others are outfitted with complex security features that indicate if a letter has been opened by someone other than the intended recipient. Jana’s research has even suggested that a single individual might have had more than one technique for folding letters.

Most of this research has been carried out by studying unfolded letters, examining folds, cuts, and other physical evidence in order to reverse engineering the original folded structure. Now, Jana and a team from Queen Mary, University of London are using Computed Microtomography (CT scanning) to discern the interior structure of unopened letters. A collection of 600 such letters is held by the Museum voor Communicatie in The Hague, Netherlands.

The letters are part of a group of 2,600 that came to the Museum stored in a 17th century trunk. Jana explained that in the period when the letters were written, the mail operated on a “cash on delivery” system. The letters in the trunk were never retrieved, and thus remained in the custody of the postmaster. While about 2,000 have previously been opened, the “Signed, Sealed & Undelivered” project team are studying the 600 that have never been opened, using a novel application of CT imaging.

During the talk, Jana shared many videos from the project website, demonstrating techniques for letterlocking and showing the potential of the imaging technique.

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