Leif GLASER | Ivan SHEVCHUK | Daniel DECKERS | Martin TOLKIEHN | Ira RABIN | Oliver HAHN
(Centre for the Study of Manuscript Cultures (CSMC), Hamburg, Germany)

Keywords: Iron Gal Ink, XRF, statistical analysis

Preparing parchment for reuse is often based on a first step of chemical erasure of the previous text, resulting mainly in a removal of the organic compounds of the iron gall ink. This way the metallic part of the ink remains in the parchment at its original place of writing. Therefore it allows nowadays to use non destructive X-Ray Fluorescence (XRF) investigations to access the original ink for local metallic fingerprint analysis and text recovery by mapping the object.
Especially in order to re-access the erased iron gall ink text non destructive modern techniques often very successfully apply different methods of optical full field techniques such as Ultra-violet and Multispectral imaging. The use of XRF complements these methods allowing an element specific probing of the writing, even if this writing is physically covered or otherwise optically inaccessible.
This paper describes the XRF mapping technique as well as ways to improve the data treatment in order to minimize the analysis time. Thus in situ visualization of the measured areas is possible, applying statistical processing in addition to the classical XRF data treatment. The new approach is showcased and optional post processing steps shown that in some cases can significantly improve the contrast of the revisualized writing.

Relevance for the conference: XRF mapping is a versitile non destructive method to revisualize faded or erased Iron Gall Ink writing or paint – important tool in the scope of the conference.
Relevance for the session: The method described in the paper actually does exactly what the session title promises.
Innovation: The data treatment is accelerated from post processing to in situ visualization, as well as the post processing itself.
• Glaser, L. and Deckers, D., Basics of fast scanning XRF element mapping for iron gall ink palimpsests, Manuscript Cultures No. 7(2014), ISSN 1867-9617,pp.104-112
• Cohen, Z. et al., (2015), Composition of primary inks in medival palimpsests – effecs of ink removal, OPUSCULA MUSEALIA 23, doi 10.4467/20843852.OM.15.007.5385 s. 75-82