The Effect of a Plasma Treatment on the Aging Behavior of Selected Artist Colorants

Abstract

ABSTRACT In this research study, the effects of an atmospheric pressure plasma treatment on the stability of selected colorants (pigments: red lead, vermilion, azurite, verdigris, smalt, ultramarine, raw sienna, vine black, champagne chalk, Bolognese chalk; dye: alizarin red) were investigated. In order to gain knowledge about the effect of a plasma on the more stable part of colorant-binder systems in works of art, binder-free colorants were first investigated. For this purpose, the samples were briefly exposed to an atmospheric pressure argon or air plasma and then stored for several weeks in two different climates: an indoor climate and a humid climate. Slight color changes were recorded in red lead, verdigris, alizarin red, and Bolognese chalk by photometric investigations and evaluation of the color values in the CIEL*a*b* system. Scanning electron microscopy revealed morphological changes in the plasma-treated verdigris samples. With the help of infrared spectroscopy and X-ray diffractometry, it could be shown that the degradation processes of some of the examined colorants were influenced by the preceding plasma treatment. Nonetheless, atmospheric pressure plasma treatment could be of interest in art restoration as a tool for decontamination and surface activation.