www.helmholtz-berlin.de

VIRTUAL ACCESS TO HIDDEN TEXTS - STUDY OF ANCIENT PAPYRI

Dr. Tobias Arlt

tobias.arlt@helmholtz-berlin.de

Fon +49-30-8062-42822

Fax +49-30-8062-43059

Introduction

HZB Tomography Station at BAMline

In the Papyrus Collection of the Egyptian Museum in Berlin (as well as in magazines worldwide) a multitude of papyri is stored, fragments of different sizes, some rolled, some folded, some quite irregular bundles. The findings of manuscripts on the island Elephantine are rather unique since they cover a period of around 4000 years with various phases of several cultures living there in close exchange. To get access to this source of profound knowledge about our cultural origin we have to reveal the texts hidden in these delicate and precious objects and make them publicly available in open access databases. In particular, the inter- and multidisciplinary research (e.g. imaging technologies) has reached a high quality in recent years [1] allowing to address this challenging task. In the case of hidden texts on parchment or papyrus, a few groups have already succeeded in revealing the texts when a good ink contrast was given [2,3].

[1] see international conferences like SR2A, TechnArt, and, initiated by one of the authors (HEM) GRC (http://www.grc.org/conferences.aspx?id=0000674), and Franco-German summer school manuSciences ’15, chairs H.-E.Mahnke and D. Stökl Ben Ezra, 2015 (http://www.topoi.org/event/29403/). [2] T. Wess, et al., Apocalypto project – Unrolling the unrollable. 2012, http://apocalypto.org.uk ;D. Mills, et al. , Apocalypto - Revealing lost text with XMT, Proc. of SPIE Vol. 9212 (2014) 921210-1. [3] H.-E. Mahnke, V. Lepper, Virtual unfolding and unrolling of papyri – identification of hidden texts, P-48 at SR2A Paris 2014, Book of Abstracts, http://ipanema.cnrs.fr/spip/IMG/pdf/SR2A-2014-Book_Livre.pdf

Elephantine

Concept When physical unfolding/unrolling is not possible or too dangerous for preserving the precious object, tomographic approaches may be the ap-propriate alternative. Requirements are the resolution and the contrast to distinguish writing and substrate. Select the object of interest (archaeological arguments, cultural back-

ground of the object, etc.) Find the proper physical procedure, especially with respect to contrast,

take the tomographic data, e.g. by absorption x-ray tomography. Mathematical treatment of the tomographic data set to obtain 2d-planar

reconstruction of text. Optimizing unrolling and unfolding procedures.

Virtual Unrolling Summary

7000 eV 7200 eV Iron distribution

Figure 4: Transmittance radiography at 7000 eV and at 7200 eV. Dark gray values means high at-tenuation, i.e. iron. First projection (“7000 eV”) has been divided through the projection (“7200 eV”) to obtain the iron distribution (see right image). Areas containing iron are shown in light gray values. This procedure was done for every angle/projection of the tomography before data reconstruction.

papyri

Figure 1: Papyri were found on Elephantine, Egypt.

Figure 2: Papyri with carbon and iron gall ink.

Figure 3: Technique of tomography and energy-selective measurements.

Iron gall ink carbon ink

Aims: Developing a procedure to get access to hidden texts in rolled / folded papyri without impacting the samples.

extrapolation

interpolation

extrapolation

interpolation

slice i

slice i+m

slice i+n

Figure 5a: Manual-ly defining a seg-mentation for spiral contours along the papyrus roll (slices i, i+m, i+n)

Figure 5b: Linear interpolation be-tween manual con-tours and constant extrapolation out-side.

Energy sensitive measurements allows for separation of ferrous areas:

Figure 6: Unrolled volume in false color. Letters “c” and “f” (both iron ink) are visible. Letter “T” (carbon ink) cannot be detected by the applied method. Particles which originally belong to the papyrus material (colored in blue), are also visible with the exception of the areas of the letters “c” and “f”. Dark stripes in the upper part are due to limited angle problem.

We are presently looking for ways in order to read the Papyri from the elephantine project. Measurements should also be feasible using con-ventional methods.

Synchrotron X-ray Imaging was successfully applied for visualization of

virtual 3D volumes of ancient papyri. Iron ink could clearly be visualized and unfolded using in-house made

software tools. Tomographic measurements at the iron k-edge allows for higher contrast between ferrous areas an those without iron.

The contrast for carbon-based ink is still too low for unambiguous visu-

alization that is mandatory for reading ancient papyri. Promising techniques for ink detection are available at Helmholtz-

Zentrum Berlin.

Acknowledgement

The expertise of the papyrus conservator M. Krutzsch (SPK) is highly acknowledged. This work is supported by the grant ELEPHANTINE of the European Re-search Council (ERC) and by the Beauftragte der Bundesregierung für Kultur und Medien (BKM) and the Regierender Bürgermeister von Berlin.

Iron content

T. Arlt1, N. Lindow

2, D. Baum

2, A. Hilger

1, I. Manke

3, H.C. Hege

2, V. Lepper

4, T. Siopi

4, H.-E. Mahnke

5

1 Technical University Berlin, Hardenbergstraße 36, 10623 Berlin, Germany

2 Zuse Institute Berlin, Takustraße 7, 14195 Berlin, Germany

3 Helmholtz-Zentrum Berlin, Hahn-Meitner-Platz 1, 14109 Berlin, Germany

4 Ägyptisches Museum und Papyrussammlung, Staatliche Museen zu Berlin, Geschwister-Scholl-Str. 6, 10117 Berlin, Germany

5 Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany