Wall Painting Essay

The analytical techniques

The analysis of wall paintings is affected by many factors; the small size of sample, the degradation processes, the multi-layers of the structure and the complexity of the mixtures (organic and inorganic compounds). The analyzing method for ancient materials should be micro or non-destructive, fast, sensitive and multi-elemental.

Optical Microscopy (OM)

The examination of painting materials usually begins with visual observations. That are useful in providing data about the stratigraphy of paint layers, their microstructure, grains size, colors, and the detection of any impurities. Paint flakes and mounted crosssections are commonly used for that purpose. Samples must be collected from hidden areas or from seriously

It is a form of vibrational spectroscopy that allows the identification of particles in the micron order. The identification is based on the molecular vibrational spectra of the samples, obtained by the excitation with visible laser light (saseas0494). In micro-Raman spectrometer, the laser beam is focused by means of microscope objectives employing a backscattering configuration (Perardi,

Zoppi and Castellucci 2000).

Red pigment samples were collected from Roman over-paintings from the reign of the Emperor Diocletian (the late 3rd century AD) at Luxor temple, Upper

Egypt. Raman spectra were recorded using a triple grating spectrometer (Dilor XY) in the red line excitation (632.8 nm). The laser was focused on the sample through the

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microscopic unit equipped to the instrument. The μ-Raman spectrum collected on a red pigment sample compared with RRUFF Raman-Database, confirmed the main characteristic bands at 226, 298 and 408 cm−1 are for hematite (Fe2O3). Moreover,

Raman microspectroscopic analysis was applied successfully to study paintings in the hypocaustum of the Roman villa of El Ruedo (Almedinilla, southern Spain) from the