H.-E. Mahnke1,2,3, T. Arlt3,4, D. Baum5, M. Etienne6, H.-C. Hege5, F. Herter1,5, V. Lepper1,7, N. Lindow 5, I. Manke3, E. Menei8, T. Siopi1

1 Ägyptisches Museum und Papyrussammlung, Staatliche Museen zu Berlin, 2 Freie Universität Berlin, 3 Helmholtz-Zentrum Berlin, 4 Technische Universität Berlin,5 Zuse-Institut Berlin, 6 Musée du Louvre, Département des Antiquités Égyptiennes, 7 Humboldt Universität zu Berlin, 8 Freelance Conservator Musée du Louvre, Paris.

Concept

E.g. µCT at HZB (Hamamatsu tube,W anode, voltage/power: up to 150kV), detectability: down to approx.10 µm, voltage used 40 or 50 kV.Volume rendering is done withAmira software.

In the writing culture of ancient Egypt, a book is generally a scroll, whileother documents are typically folded with specific purpose dependenttechniques. While virtual unrolling of scrolls is relatively straight forwardeven when severely distorted, virtual unfolding can be challenging,depending on the type of fold, especially when orthogonal folding linesoccur as in the so-called magic fold.

Step 2 X-ray Absorption Tomography

Step 1Select the object of interest (archaeological arguments, cultural background of theobject, e.g. Elephantine, etc.).Step 2Find the proper physical procedure, especially with respect to contrast, by e.g.performing XRF, acquire tomographic data by e.g. x-ray absorption tomography.Step 3+

Visualize the tomographic data to determine rolling or folding technique for anoptimal virtual unfolding procedure to obtain a planar presentation of the text.Apply the virtual unfolding procedure and create visualizations that highlight existingtext fragments in individual layers.

Identify ink containing high Z-value elements by means of a portable XRF

Acknowledgement and ReferencesWe thank K. Mahlow and J. Müller (Museum für Naturkunde, Berlin) for getting the first tomography dataon their GE Phoenix Nanotom S for the magic fold mockup and first attempts on packages from thePapyrussammlung. We are grateful to L. Glaser (DESY, Hamburg) who wrote the cinnabar and miniumink letters, to F. Kutz and Ph. Hoelzmann (FU FB Geo and TOPOI) for his help with the Niton pXRF, andto E. Laval who let us check the Louvre objects at the C2RMF with their ELIO pXRF.This work is supported by the starting grant ELEPHANTINE of the European Research Council (ERC)and by the Beauftragte der Bundesregierung für Kultur und Medien (BKM).

[1] M. Krutzsch, Falttechniken an altägyptischen Handschriften, in: Ägypten lesbar machen – die klassische Konservierung/Restaurierung von Papyri und neuere Verfahren, Archiv für Papyrusforschung Beiheft 24, 2008, Berlin/New York, 71–82

[2] D. Baum, N. Lindow, H.-C. Hege, V. Lepper, T. Siopi, F. Kutz, K. Mahlow, H.-E. Mahnke, Revealing hidden text in rolled and folded papyri, Appl. Phys. A (2017) 123:171

Ink in mock-up scroll: cinnabar and minium(XRF taken with NITON with 4-mm beam spot).

Virtual Unfolding of Folded Papyri

Ink in Louvre object L / EP227b/2-pU: iron gall ?(XRF taken with XGLab ELIO with 1-mm beam spot).

Louvre Museum, Paris Brooklyn Museum, NYÄgyptisches Museum und Papyrussammlung, SMB

Select object out of Elephantine box:

X-raysX-rays150kV X-ray source

fragment detector

Fe

Unfolding of Elephantine Packages

The vertical cuts through the object indicate orthogonal folding lines.

Inside, Coptic letters become visible after reconstruction.

“Greek” package L/EP 227b/4-pG.

Step 3 Visualization and Unfolding

Mock-up (“magic fold” [1])

- Warp the whole image based on these newly computed contours.

Iterative virtual unfolding of a papyrus package folded along 2 perpendicular foldinglines (using moving least squares) until the result can be virtually unrolled [2].

- Define outer contour (blue) and medial axis (red).- Flatten medial axis and deform outer contour.

- Iteratively adapt the 2D distances to the 3D distances in the tomogram to minimize the distortion.

Step 1

“Magic fold” L/EP227b/2-pU ?

2D-projection along brownish line, recto and verso. No letters are found.

Two folds from both sides were identified, the recovered layers, heavily damaged near the folding lines, show various Greek letters.

a

b c

a

b c

Perpendicular cuts along a, b, and c

“Coptic” package L/EP 227b/1-pC

These objects, all rather delicate and brittle, illustrate the need for virtual methods to get access to hidden text.