A Preliminary Investigation into the Behavior of Modern Artists’ Oil Paints in a Hot and Humid Climate

Abstract

Understanding how modern oil paints are vulnerable to change in tropical conditions is key to developing place-based conservation approaches for paintings produced and located in Southeast Asia. This study is an examination of reference paint films on canvas naturally aged under ambient indoor conditions in Kuala Lumpur, Malaysia, and Melbourne, Australia, representing exposure to tropical and temperate conditions respectively. Paints from two widely available artists’ colourmen, Winsor & Newton and Marie’s, were selected, and their behavior assessed for: titanium-zinc white, earth brown and a red from each range. Physical and chemical differences in the two sets of paints were characterized using optical microscopy, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (ATR-FTIR), and X-ray photoelectron spectroscopy (XPS). The results indicated significant differences in the chemical composition and structure of the paints after ageing. Those aged in Kuala Lumpur exhibited a greater degree of hydrolysis and formation of metal carboxylates, while we postulate additional degradation pathways related to the presence of specific additives and the ambient environment. A better understanding of these processes can be used to inform much needed preventive and interventive conservation approaches for museum collections located in tropical climates.