This article attempts to highlight a phenomenon that more or less permanently damages emulsion paint layers, the surfaces of which remain sufficiently permeable for dust particles to become permanently anchored there; when the particles are nanometric, this can cause a permanent change in appearance. Based on scientific documents, empirical observations, laboratory analyses, case studies, and reconstructions of characteristic pictorial layers, this paper aims to highlight the medium- and long-term risks that alter these surfaces, in order to realize strategies for better prevention. The physico-chemical nature of these vulnerable materials will be discussed first, followed by the dust’s involvement; finally, the topic will be illustrated through concrete examples, with photos taken using digital, 4 K optical, and Scanning Electron Microscope equipment (SEM), in order to show how the problem of dust particle accumulation impacts even the most contemporary works of art.

The use of organic solvents in treatments for the removal of varnishes on easel paintings is still a common practice among conservators worldwide. The more polar solvents required for aged, oxidized varnishes may promote leaching of fatty acid components of oil-based paints. The strategy tested in this study to reduce the diffusion of the solvents, in an attempt to minimize interactions, relied on the use of a system composed of two devices: a pump for delivering a precisely controlled amount of solvent to the surface, and a solvent-proof membrane pump to quickly aspirate it. This method was compared with two traditional methods of solvent application, to remove the varnish on two oil paintings on canvas, one from the twentieth century and the other dated 1872: swab-rolling and application through a Japanese paper sheet. The extent of leaching was measured by GC−MS analysis of the paint samples taken from the treated areas. The profiles of the fatty acids before and after varnish removal could thus be compared.