by Beskhyroun, S., Magoub, G., Elserogy, A., Darwish, S. and El-Rifai, I.
ABSTRACT
This research is the outcome of an integrated diagnostic study that has been performed to assess the conser-vation state of the oil painted portrait of Mohamed Ali Pasha at the National Military Museum, Citadel of Saladin (Cairo) in preparation for conservation interventions. Documentation methods, micro-stratigraphic examination and chemical studies were conducted to characterize the painting materials, technique and the physiochemical changes that occurred on. The painting was imaged by Multi-spectral imaging (MSI) and sam-ples were collected from representative areas. Cross-sections from the previous conservation interventions added to the original painting structure, varnish, pigments, medium, ground layer, canvas support and wooden stretcher were studied by the means of stereomicroscopy (SM), scanning electron microscope coupled with dispersive energy of X-ray spectrometer (SEM-EDS), Attenuated total reflection-Fourier transform infra-red spectroscopy (ATR- FTIR), Gas chromatography-mass spectroscopy (GC-MS), and X-ray diffraction (XRD). The studies resulted in the characterization of the deterioration phenomena that occurred to the origi-nal painting materials of linen canvas support, the ground layer of barite, calcite, hydrocerussite, zinc oxide and the followed oil painted layer. Discoloured dammar varnish and non-systematic previous conservation intervention affected the appearance of the painted layer of burnt sienna, green earth, red ochre, and ultrama-rine with the mixtures of lead-based pigments. It was concluded that the painting was incompatibly conserved more than once with destructive consequences to the painting aligned with chemical changes occurring to the paint medium and the varnish.
