Despite the large body of ancient Ethiopian works of art in the form of murals, icons, and illuminated manuscripts, the physicochemical examinations carried out on them are few. This study is an in situ investigation of the wall paintings in the early 12th century Yemrehanna Krestos Church, Ethiopia. Fast, onsite, nondestructive analysis of the painting materials was carried out using a portable X-ray energy fluorescence dispersive spectrometer. It is believed to be the first onsite technical examination of Ethiopian mural paintings. This work resulted in information about the painting materials and the existence of different painting programs. The analysis revealed that the main pigments were red and yellow ochre, minium, cinnabar, orpiment, gypsum, lead, and white and carbon black; those typically employed in medieval times with no indication of later conservation-restoration intervention. Correlation between concentration of elements and multivariate statistical analysis was used to identify the most probable compounds and to classify sets of pigments used in two painting programs. The portable X-ray energy dispersive fluorescence spectrometer analyzer is found valuable to guide the in situ analysis and assess potential sites for microsampling for further investigations with complementary analytical techniques. However, in this expedition, we were unable to collect sufficient microsamples to warrant adequate complementary analyses. Characterization and documentation of the materials of the church murals support art historical studies and eventually conservation intervention plans.

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ABSTRACT. The levels of essential metals (Ca, Mg, Fe, Mn, Zn, Cu, Co, Cr, Ni) and toxic metals (Cd, Pb) were determined in the leaves of Croton macrostachyus (traditional medicinal plant) collected from four different regions of Ethiopia (Akaki, Abomsa, Bonga and Dilla) and also in the infusions of leaves collected from Akaki using flame atomic absorption spectrometry. An optimized digestion procedure took 2.5 h for the digestion of 0.5 g of powdered sample with 2 mL of HNO3 and 2 mL of HClO4 at 270 o C while 2 h were needed to digest 25 mL infusion with 4 mL of HNO3 and 1 mL HClO4. The recoveries of metals were in the range 92-103% for the leaves powder and 94-105% for the infusion samples.

Abuna Yemata Guh is one of the nine Saints who are traditionally claimed to have come to Northern Ethiopia in the beginning of the sixth century and established monasteries in the Tigray region. The church, named after him, is hewn out of the side of one of the highest sandstone spires in the Gheralta area. Though the local tradition claims earlier dates, the paintings in the church are suggested to belong to the second half of the fifteenth century on the basis of their theme, style and iconography. We report here the investigation into the materials and techniques of the paintings using diverse complementary analytical techniques: Polarized light microscopy (PLM), portable X-ray fluorescence spectrometer (pXRF), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), synchrotron-based X-ray diffraction (SR-XRD), pyrolysis gas chromatography-mass spectrometry (Py-GC/MS), microRaman spectroscopy (MRS) and micro-Fourier transform infrared spectroscopy (micro-FTIR). Earth materials based on hematite, goethite and terra verte were the main findings, but cinnabar, orpiment, lead white and carbon black were also identified. The stratigraphic analyses of samples from different locations coupled with SR-XRD analysis indicated the presence of anhydrite, gypsum, calcite and lime in the preparation layer. The pigments identified together with close visual examination showed repainting and retouching within the area in which the Marian figure is depicted, as well as in a nearby figure. The ground preparatory layer consisted of red mud reinforced by straw applied to the chiseled sandstone support. The egg-based binding medium suggests that tempera technique was used. Technical studies of Ethiopian wall paintings are scant, but highly needed as this world heritage is threatened due to limited conservation. Our documentation of the materials and techniques is therefore aimed to stem this loss, as well as to provide information for art historical studies.

Here, we report the physico‐chemical characterization of wall paintings from the Petros and Paulos church in Ethiopia. This work represents the first technical study of paintings located in Ethiopia, rather than paintings in museum collections outside the country, using diverse analytical techniques. In situ examination with a portable X‐ray fluorescence spectrometer (pXRF) was followed by analysis of samples using optical microscopy (OM), scanning electron microscopy coupled with energy‐dispersive X‐ray spectroscopy (SEM/EDS), micro‐Raman spectroscopy (MRS), attenuated total reflection – Fourier transform infrared spectroscopy (ATR‐FT–IR), X‐ray powder diffraction (XRD) and pyrolysis gas chromatography – mass spectrometry (Py‐GC/MS). The paint stratigraphy, the compositions of the support material, the preparatory and painting layers were studied, as well as the morphology of the pigment particles. The results revealed the use of earth pigments and carbon black. The preparatory layer was uncommon; composed of dolomite, clay rich in clinochlore and sand, in contrast to the more common gypsum and calcite. The binder and the stratigraphic analyses suggested a distempera technique.