Analysis and conservation of modern modeling materials found in Auguste Rodin's sculptures

Abstract

Prior to the exhibition Portrait-making, Rodin and his models (2009), the Rodin museum wanted to restore two busts of Hanako and Clemenceau. Interestingly, these two sculptures contain pieces of modern modeling materials (MMMs) invented at the end of the nineteenth century as an alternative to clay or waxes. The poor state of conservation of the two portraits made any handling and exhibition impossible. Accordingly, the purpose of this article is twofold: to contribute to technical art history and conservation. Elemental and chemical analyses were done on samples from 12 sculptures (SEM-EDX, FTIR, GC-MS, GC-FID, XRD, synchrotron-based μXRF, μXANES, and μFTIR) aimed at identifying the composition of MMMs used by Rodin on plaster sculptures and establishing hypotheses about the origins of their degradation. This thorough study of their composition and degradation was necessary to implement an appropriate restoration plan. The development of conservation protocols adapted to such materials is rarely documented. Different tests were performed on mock-ups (pH, solubility, adhesion, consolidation, and cleaning). In particular, a protocol based on laser cleaning was developed and successfully applied to remove superficial dust and crusts so that the sculptures regained their original aspect.

Research on Optimization of Portrait Sculpture Data Based on 3D Image and Mobile Edge Computing

“…The contour method is to restore the structure from the contour, which is to restore the three-dimensional shape through the contour line constraint of the multi-view image. In this method, the target scene is regarded as a cone in space, and the contour map of the target scene in multiple images is extracted through a calibrated camera, and the spatial position information of the cone is calculated [29][30]. When the same target acquires multiple images in different orientations, multiple contour information can be acquired in the three-dimensional space, thereby generating the geometric topology of the target scene.…”

Application of Synchrotron Radiation-Based Micro-Analysis on Cadmium Yellows in Pablo Picasso's Femme

“…In general, elemental, chemical speciation, and crystalline phase maps can be obtained by raster scanning the sample over 2D regions. Less frequently, SR X-ray analyses are combined with other SR-based techniques, such as micro-photoluminescence ( μ PL) or micro-Fourier Transform Infrared ( μ FTIR) spectroscopy (Salvadó et al, 2011, 2014; Lluveras-Tenorio et al, 2012; Pouyet et al, 2015; Langlois et al, 2017; Gonzalez et al, 2020 b ). Such non-X-ray techniques provide complementary information on the molecular composition, offering a unique integrated approach for the analysis of painting materials.…”

Modelling clay materials used in artworks: an infrared spectroscopic investigation

“…Modelling clays have long proved popular for use in sculptures due to their malleability and non-drying attributes. There has been a history of the use of natural clays and waxes in sculpture and commercial modelling materials have been in use since the end of the nineteenth century, with materials, such as Plasticine, developed at that time [1][2][3]. Plasticine was formulated in 1897 in England to produce a non-drying clay suitable for use by sculpture students.…”

“…A range of commercial compositions have followed, using different components to produce a variety of physical properties. Despite their use over an extended period of time, a recognition of the diverse composition types and information reported about the long-term stability of such materials in artworks has been very limited [1].…”

“…The first modelling clay formulations appearing in the nineteenth century, such as Plasticine, were oil-based materials. Such materials are a combination of oils, waxes and minerals [1,2,4]. A range of oil and wax components have been used, including, for instance, paraffin, beeswax, microcrystalline wax, petroleum jelly, palm oil, castor oil and lanolin.…”