Investigating the morphological and chemical characteristics of surviving neo-rococo wall paintings in Egypt

Cairo's 19th-century buildings with historic and cultural importance are decorated with a prosperous coloring palette. In the present work, samples of pictorial layers and gilded surfaces from El-Gawhara Palace, the Great mosque of Muhammad Ali Pasha, and the Palace of Shubra were studied. Since there is a research gap concerning the painting materials in those monuments, the present study aims to characterize the pictorial surfaces in the studied buildings and to compare the results with other paintings from the same period. The material characterization included microscopic examination via an optical digital microscope. The surface morphology, microstructure, and the elemental identification were accomplished using a field-emission scanning electron microscopy and energy-dispersive X-ray micro-analyzer. In addition, Fourier transform infrared spectrometer was used to confuin some findings. The results allowed a sufficient understanding of the paint layers and their chemical nature. The analytical methods revealed ultramarine blue (Na7Al6Si6O24S3) as the blue coloring material in the studied buildings. Further, an obvious discoloration in the blue paint layer from El-Gawhara Palace was reported. Green earth was identified in the great mosque of Muhammad Ali Pasha and in Shubra Palace. Lead (II) oxide (massicot, PbO) was used for the yellow color in Shubra Palace and a mixture of lampblack and magnetite (Fe3O4) was possibly used for the black color in El-Gawhara Palace. For the gilding technique in Shubra Palace, mechanically adhered gold-silver leaves were preferred.

Automated summary

The study aims to characterize the pictorial surfaces in 19th-century buildings in Cairo and compare the painting materials with other paintings from the same period. Through microscopic examination and analytical methods, the research revealed the use of different coloring materials and techniques in the studied buildings, providing insights into the historical painting practices in Cairo.