Synergistic use of Py–THM–GCMS, DTMS, and ESI–MS for the characterization of the organic fraction of modern enamel paints

Abstract

Introduction:In this study, mass spectrometric techniques (THM-Py-GCMS, DTMS and ESI-MS) have been used to characterize the organic fraction of early twentieth century oil-based enamel paints. Analysis has been carried out on dry and liquid samples from historical reference paints, and on color swatches from commercial paint brochures, with a special focus on Ripolin. This renowned French brand of enamel paints, manufactured for household and other uses since 1897, was reportedly used by many avant-garde artists. Confirming the presence of enamel paint such as Ripolin in early twentieth century artworks scientifically through binding medium analysis is challenging because, until the end of the Second World War, the most widely used house paints were oil-based and chemically similar to artists' oil paints. In addition, artists often modified/reformulated materials including oils, driers, industrial and house paints to customize their handling and optical properties. The challenge of identifying oil-based enamel paints on the basis of chemical composition is illustrated by the analysis of samples from two paintings by Wassily Kandinsky and Pablo Picasso.Results: Analysis demonstrated that the organic fraction of Ripolin paints is typically composed of heat-bodied linseed oil in mixture with variable amounts of diterpene (Pinaceae) resin, in accordance with the industrial technical literature of the time. Comparative analyses of Lefranc artists' tube paints suggested a more variable composition with respect to the type(s) of oil and their pre-treatment, and showed the presence of Pinaceae resin at trace levels only in two cases. Beeswax was detected in one of the tube paints tested. Conclusions:The results of this study indicate that complementary information can be obtained from the study of liquid paint from cans and dried paint-outs, while the media of painted brochures may differ from the original formulation as those were designed for expediency of drying and aesthetics. The results also elucidate how formulations and processing technology influence the physical and drying properties of oil-based enamel paints, in comparison with contemporary artists' oil tube paints. Further research on a broader range of reference materials should help in the development of refined strategies for characterizing oil-based paints from the early twentieth century.

Disclosing Jackson Pollock’s palette in Alchemy (1947) by non-invasive spectroscopies

“…8a-e) [28]. A differentiation between oil house paints and artists' oil tubes would be of interest in this context, but is not achievable by FTIR spectroscopy and requires micro-destructive mass spectrometry analysis [29]. As a preliminary step oriented to guide the sampling campaign, non-invasive FTIR spectroscopy enabled us to roughly classify Alchemy's oil-based paints considering signals from additives, alteration products or, more loosely, the entire spectral profile in combination with the visual differences in term of texture, body, and type application of the paints.…”

Charting the Development of Oil-Based Enamel Paints Through the Correlation of Historical Paint Technology Manuals with Scientific Analysis

“…4) (Kokkori et al 2013) a practice also described in the literature (Horton Sabin 1904;Uebele 1913;Cruickshank 1915). Castor oil was identified only in two samples of red Ripolin paint pigmented with alizarin; the identification of other types of drying oil such as soybean, perilla or fish oil recommended in the technical literature was not possible because of the lack of specific chemical markers for these materials.…”

“…On the other hand, preliminary analyses of binding media in artists' tube paints carried out for this study suggested a higher degree of variability in formulations with respect to oil types and additives. The organic components of the Ripolin and tube paints will be discussed in more detail in separate papers (Kokkori et al 2013(Kokkori et al (in preparation), 2014.…”

Anwendung der analytischen Pyrolyse zur Untersuchung organischer Materialien in Kulturgütern

“…In einer umfassenden Studie von Kokkori und Mitarbeitern wurden THM/Py‐GC/MS, DTMS und Elektronenspray‐Ionisation‐MS (ESI‐MS) zur Charakterisierung der organischen Bestandteile von Öl‐basierten Enamel‐Farben des frühen 20. Jahrhunderts benutzt.…”