Using computerized algorithms and an X-ray scanner designed for dental research, an international team of researchers has revealed the secrets of a well-folded letter sealed since 1697 – without opening it.
The “virtual unfolding” of the letter – the culmination of a four-year project described in a paper published Tuesday in the journal Nature Communications – points to a new line of historical research into the centuries-old practice of letters. This is the term used to describe the use of origami-like folds to hide the contents of letters before envelopes were widely used in the mid-1800s.
“This is a dream come true in the field of conservation,” said Jana Dambrogio, curator of the research library at the Massachusetts Institute of Technology and one of 11 authors.
Experts say the technique used to reveal the text of the letter, which includes a type of imaging called X-ray microtomography, could also have applications in health and engineering.
Letterlocks varied in complexity, depending on the expertise of the sender and the receiver and how obvious they were to have their messages in transit. Some involved dozens of folds, resulting in packs the size of playing cards.