The Irreplaceable Contribution of Cross Sections Investigation: Painted Plasters from the Sphinx Room (Domus Aurea, Rome)

Alessia Coccato,Roberta Occhipinti,Germana Barone,Alessandro D’Alessio,Maria Cristina Caggiani,Paolo Mazzoleni,Alfonsina Russo

doi:10.3390/min11010004

Alessia Coccato, Roberta Occhipinti + Show 5 more

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https://doi.org/10.3390/min11010004

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Journal: Minerals	Publication Date: Dec 22, 2020
Citations: 3	License type: CC BY 4.0

Affiliation: University of Catania, National Archaeological Museum

Abstract

Fragments and micro-fragments of painted plasters from the Sphinx Room, recently discovered in the Domus Aurea Esquiline wing (Rome, Italy), were studied. They were respectively taken from the debris in the vicinity of the walls and from already damaged edges of the decorated walls. A previous study, mainly based on non-destructive and non-invasive investigations, proved effective in giving a general overview of the employed palette, allowing the comparison with paintings from the same palace and other coeval contexts, and also providing some preliminary hints concerning the pictorial technique. Nevertheless, some issues remained unsolved, concerning the pigment mixtures (e.g., lead-/iron-based yellow to red colors; copper-/iron-based green/greyish areas), and the a fresco/a secco painting technique debate. Therefore, cross sections of the above-mentioned fragments were observed by means of Optical (OM) and Scanning Electron (SEM) Microscopy and analyzed with micro-Raman spectroscopy and Energy Dispersive X-Ray Spectroscopy (EDS), with the aims of: studying the paint layer composition through point analysis and mapping of the elemental distribution; comparing these in relation to what was observed with previously reported non-destructive analyses; studying the stratigraphy of the painted plaster, focusing on the contact between the plaster and the paint.

Highlights

Nero’s (37–68 AD) Domus Aurea was built by Severus and Celer after 64 AD, and decorated by the famous painter Fabullus ([1] XXXV, 120)
One of the insights of optical and electronic microscopy observations of the eight samples’ cross sections was on their stratigraphy, with the aim of examining the number and thickness of pigmented layers, as well as the features of the contact between them, such as morphology and sharpness. All this information can be compared with objective microstratigraphic criteria experimentally searched for in order to distinguish between fresco and lime-painting [34]
A variety of painting techniques has been highlighted by cross-section observation, both with optical and electron microscopy, encompassing one or more a fresco layers, as well as the use of lime paint

Summary

Introduction

Nero’s (37–68 AD) Domus Aurea was built by Severus and Celer after 64 AD, and decorated by the famous painter Fabullus ([1] XXXV, 120). Investigations on Domus Aurea decorated surfaces were carried out mainly to address conservation issues [3,4,5,6,7], while the studies concerning the mural paintings composition aimed at understanding the pigments and painting techniques employed are very few [5,8,9,10]. The previously used approach [10] did not allow to unequivocally identify the painting technique, and some unclear points remained concerning the pigmenting agents. Even though lately a non-destructive, complementary, minimally invasive approach is favored in archaeometric research, with the extensive in situ application of multi-analytical approaches, it often leaves numerous questions unresolved, such as the painting technique and the mixtures used [5,8,10,11]

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