MULTISCIENTIFIC ANALYTICAL APPROACH OF POLYCHROME GRECO-ROMAN PALETTE APPLIED ON A WOODEN MODEL NAOS: CASE STUDY

Abstract

In this paper, a nondestructive multiscientific analytical technique approach was used in order to map and identify how the palette of pigments and the painting techniques used by ancient Egyptian artisans on wooden substrate, since old kingdom to the New Kingdom (2575-1070BC), have been developed and enriched in the Greco-Roman period (30 BC-AD 311). For first time the multiscientific combined methodology is applied on a polychrome naos dates back to Greco-Roman period, and shed light on the degradation of some of this pigments. The painted materials layered on the wood surface were analyzed by several scientific methods; optical microscopy (OM), technical photography, X-ray fluorescence (XRF), X-ray diffraction (XRD), SEM, FTIR-ATR, Imaging techniques (IR, VIL, UV). The application of technical photography provided useful information about the spatial distribution of the surviving original pigments, in particular visible-induced luminescence, which played an important role to recognize spatial distribution of areas containing Egyptian blue, Ultra violet induced luminescence emphasize using two kind of white pigments. The results obtained by this technique indicate that the brown color is obtained by using a mixture of black (ivory black) and red pigment (cinnabar) which considered a new developing for the methods commonly used for obtaining brown color. Besides using lead white in the areas of bright white as overpaint for dull white substrate, using mixture of Egyptian blue and earthy green to obtain bluish green, the use of Huntite as an underpaint layer over the preparation layer in the yellow pigment area is due to its bright white color that reflects light from the paint and gives it more color saturation and brightening and yellow pigment is orpiment, however examination indicate that areas of degraded orpiment appear off-white.