During treatment of „The Dismissal of the Lictors” in the restoration department of the Princely Collections
Procedures and Methods
During the course of the project the entire "Decius Mus cycle" is being extensively analysed to better understand the material usage and the painting technique(s) employed. Different imaging methods are used to document the work and help detect possible, earlier, modifications or changes in the painting procedure. In this process, the works are examined using rays of varying wavelengths (Ultraviolet , Visible, Infrared, X-rays).
X-ray imaging is additionally used to analyse the weave structure of the canvases. Alongside non-destructive methods such as X-ray fluorescence analysis (XFA) to identify pigments, minimal material samples are taken to determine the binding agents (oil/glue, etc.) through gas chromatography/mass spectrometry – GC/MS. Further paint samples will be embedded in resin and sectioned to show the layering of the original paint applications, and in cases the presence of later restorations. To determine the geological origin of the lead-based white pigment in the paintings, lead isotope analysis will be used.
The analyses were carried out in collaboration with the Natural Science Laboratory of the Kunsthistorisches Museum Vienna, the Institute for Natural Sciences and Technologies in the Art (Academy of Fine Arts Vienna), the Curt-Engelhorn-Zentrum Archäometrie gGmbH, the Department of Wood Biology (Institute of Wood Sciences, University of Hamburg) and the Institute of Electrical & Computer Engineering (Rice University).
Conservation and restoration work have their own extensive specialist vocabulary. Here you’ll find explanations of the terms, processes and methods that occur in the text.
X-ray imaging and infrared reflectography show that Rubens first laid down his figures with underdrawing, sometimes shifting their position. A grid system was used to transfer the composition of the “modello” to the larger format.
All the compositions were originally painted in reverse (mirror image), as were the cartoons of the same dimensions, which were used as models for the weavers of the tapestries. The inscriptions (“SPQR”) were subsequently later painted over (non-reversed), so that the paintings could also function (later) as autonomous works.
Cross-section analysis using reflected light and scanning electron microscopy can reveal the structure of the ground and layers of paint, and identify the pigments contained in the samples.
X-ray fluorescence analysis (XRF) allows non-destructive identification of pigments directly on the painting. The material composition of a paint passage within a single site is analysed. The elements detected serve as a basis for interpretation of the pigments and extenders within the various layers of paint, allowing conclusions to be drawn as to the working palettes(s) of the studio.
