https://phys.org/news/2018-07-mystery-basel-papyrus.html

One of these Amerbach papyri was regarded until now as unique in the world of papyrology. With mirror writing on both sides, it has puzzled generations of researchers. It was only through ultraviolet and infrared images produced by the Basel Digital Humanities Lab that it was possible to determine that this 2,000-year-old document was not a single papyrus at all, but rather several layers of papyrus glued together. A specialist papyrus restorer was brought to Basel to separate the sheets, enabling the Greek document to be decoded for the first time.

"This is a sensational discovery," says Sabine Huebner, Professor of Ancient History at the University of Basel. "The majority of papyri are documents such as letters, contracts and receipts. This is a literary text, however, and they are vastly more valuable."