Design & study of cost-effective conservation of watercolor paper

Abstract

One of the concerns of watercolor artworks on paper is the natural oxidation process of the paper, leading to the development of unsightly yellow-brown spots referred to as foxing. Historically, efforts to preserve watercolor pieces in museums, institutions, and private collections have relied on intricate and expensive techniques. Unfortunately, these methods are not practical for the broader community of artists and less affluent collectors. Furthermore, the introduction of foreign preservation materials, which can interact with the artwork's components, poses a risk to the original visual appeal. Consequently, watercolor art collections have lost some of their appeal compared to oil paintings on canvases. This study endeavors to offer an alternative, straightforward, and cost-efficient approach to safeguarding watercolor artworks created on high-quality watercolor paper, a type commonly used by typical watercolorists, making it a suitable candidate for this investigation. This approach also avoids introducing additional substances to the artwork. The protective technique involves the application of commercially available acrylic gesso to a fresh sheet of watercolor paper. This gesso-coated paper serves as a backing for framing and displaying the original watercolor artwork, without the need for any foreign preservation materials to be added to the artwork itself. To assess the effectiveness of this protection method, a comparison was made between the foxing tendencies of protected and unprotected paper artworks stored for a decade. These samples were subjected to various analytical techniques, including optical microscopy (OM), confocal laser scanning microscopy (CLSM), field emission scanning electron microscopy with energy dispersive X-ray spectroscopy (FESEM-EDX), X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and thermogravimetric analysis (TGA). The results revealed that, when compared to untreated samples, rarely any foxing spots were observed on any of the treated samples, and both the oxidation and degradation of cellulose fibers were diminished. Additionally, the analysis showed that the acrylic gesso comprised inorganic components such as calcium carbonate (CaCO₃), dolomite (CaMg(CO₃)₂), rutile (TiO₂), and organic acrylics. The carbonates created a mildly alkaline environment, neutralizing the acidity in the paper. The titanium dioxides exhibited biocidal and fungicidal properties due to their photocatalytic characteristics. The acrylic component bound and dispersed the inorganic constituents, and the coating formed a less impenetrable barrier layer as indicated by the scanning electron microscopy (SEM) results. In addition to significantly improving the resistance of the paper to foxing, the methods outlined in this study are highly cost-effective and readily accessible to artists and collectors. Importantly, they do not involve the addition of any restoration materials to the original artworks.