The Papyrus Collection of the Egyptian Museum of Berlin contains several thousand papyri, among them countless fragments of various sizes, some folded, some rolled, some wrapped up. The writing of the scripts are often hidden from the viewer in inner areas and are frequently inaccessible to methods that are only sensitive to areas close to the surface. The time-consuming physical unfolding process always runs the risk of damaging the fragile objects. Alternatively, non-destructive depth-sensitive methods offer access to the hidden texts and help to interpret them with respect to the time frame.

Unless the text itself already gives a date or provides strong links to the time, the material analysis gives complementary information. In addition, the location, the place where the papyrus was found or, better, where the material was processed and the texts written, are further helpful information to determine the relation to the time frame. The analysis of the materials used is also essential to decide which technique will be most effective and successful for the virtual unfolding and what ideas in ink-making were used at what time over a period of 4000 years of cultural history in Egypt.

Computer tomography represents the possible approach at the current stage of development to make hidden texts of papyri readable. It also promises to make characters on opposing pages readable at a resolution in the sub-micrometer range. However, standard X-ray absorption tomography requires an adequate level of contrast between the ink and the writing surface (papyrus, parchment, paper, etc.). This can only be achieved when ink made of substances containing metal ions was used, for example iron gall ink, blue vitriol, or copper etc. This procedure of standard X-ray absorption tomography was successfully applied in the ERC funded project ELEPHANTINE, led by Verena Lepper and first results were published as illustrated in figure below.

However, many of the papyri in the Berlin museum predate the successful application of this technique, which is commonly assumed. Since these papyri are primarily written with carbon ink (so-called lampblack ink - carbon powder ink), alternative methods that yield virtual access to hidden texts are required. Different approaches have to be pursued, among them various scattering techniques, phase contrast techniques, or totally different wavelength of the applied radiation like infrared or THz-radiation. Following the last mentioned idea, first tests have been started at the infrared beamline IRIS at BESSY (Berlin electron storage ring for synchrotron radiation) with promising results so far. For the alternative approaches, this project cooperates with the Herculaneum papyrus project, conducted by Vito Mocella, with similar objectives.

Our goal is to successfully identify and date hidden texts on folded sheets of papyrus. In a best-case scenario, the team would succeed in unfolding complicated papyrus packages in virtual space and exposing the completely hidden texts. This way they can be read, interpreted and dated in time.