New insights into XXI century commercial artists oil paints. Morfological and molecular aspects during drying and curing

Abstract

The study of the film-formation of XX-XXI century commercial artist oil paints has been extensively addressed over the last decade. The present thesis aims to determine a methodology suitable for understanding the interactions between oil and pigment and between pigment and pigment during the film formation processes. The research project was carried out in collaboration with the Universitat Politècnica de València (UPV) and the results obtained will be channeled into a larger project called “MIMO” -Metal Ion Migration mechanisms in Oil paints drying and degradation. The first phase of the research consisted in the preparation of a wide and uniform set of samples, by casting two main groups of painted films: group A) containing single-layered paint films; group B) encompassing side-by-side and/or superimposed painted layers to films of lead white casted in 1990, 2007, 2019, 2021 and 2022. A multi-analytical approach has been adopted to gather information about the composition of selected commercial oil paints and their variation over the time. In the characterization phase, invasive and non-invasive analyses (such as Fourier Transform Infra-Red spectrophotometry, X-Ray-Fluorescence Spectrometry, Gas Chromatography-Mass Spectrometry) were performed. Starting from the information obtained, further analyses were carried out to observe the chemical and physical changes and in order to achieve information about the processes which are in act during the phase of drying, curing and ageing in the film formation processes. Thus, spectroscopic, chromatographic, thermal, microscopic and weight analyses have been performed thorough a wide range of time. The results allowed us to discriminate the pigments that most interact with each other and with the binder. Moreover, the procedure followed was able to highlight of the influence of the pigment- pigment and pigment-oil interactions in the phases of film formation and over time. The outcomes are then applied to selected case studies from the Institut d’Art Modern of Valencia (IVAM) and the International Gallery of Modern Art of Venice (Ca’ Pesaro).