Non-destructive spectroscopic investigation on historic Yemenite scriptorial fragments: evidence of different degradation and recipes for iron tannic inks.

Six fragments of different Yemenite manuscripts (three on parchment and three on paper) were analyzed by means of attenuated total reflectance Fourier transform infrared, micro-Raman and X-ray fluorescence spectroscopies. The combination of molecular and elemental techniques allowed the characterization of the conservation state of all the fragments, the identification of sizing agents and salts on the supports and the identification of the composition all red and black writing media. In particular, analysis of black inks provided interesting insights: independent of the substrate, all inks seemed to have identical composition, corresponding to rather well preserved high-quality iron tannic inks to which carbon black had not been added. However, in some samples, the most intense Raman peak of the ink was clearly shifted with respect to the typical bands of iron gall ink. Starting from the hypothesis that the shift could have been produced by the use of sources of tannin other than gallnuts, research was undertaken by preparing and characterizing seven different tannic inks. The experimental results confirmed the hypothesis of different tannin sources.

The Indian drawings of the poet Cesare Pascarella: non-destructive analyses and conservation treatments.

The Italian dialect poet Cesare Pascarella travelled all around the world, noting down in notebooks his keen and caustic observations, and drawing sketches that are a visual reportage of his journeys. The sketches were mounted as a random collage over acidic cardboards that were exposed to direct sunlight in his studio. Their poor state of conservation is related to the use of modern paper: chemical instability of raw materials caused acidification and strong oxidation of the support, with intense yellowing of the surfaces and brittleness of the paper. To ensure future preservation of the drawings, chemical stabilisation with simultaneous alcoholic treatment by deacidification (calcium propionate) and reduction (borane tert-butylamine complex) appeared necessary. To verify its applicability, it was indispensible to characterise the support and identify the nature of all the graphic media. The use of Raman, Infrared, X-ray fluorescence spectroscopies and scanning electron microscopy coupled with X-ray microanalysis allowed us to clear the problems related to the different penetration depth of each analytical technique and the different responses of pigments/dyes to each spectroscopy. The palette, how it varied along the journeys, the different supports used and preparations were completely identified showing a choice of colours compatible with the reduction treatment.