Studies of the medium-term effect of nanoconsolidants on wall Paint Layers with a lack of Cohesion

Abstract

This paper reports an updated overview of a comparative study on the medium-term effects of treatment with three consolidants—laboratory-prepared nanolime, commercial nanolime, and commercial acrylic resin—on fresco paint layers replicas affected by lack of cohesion. This is a follow-up to our preliminary data published in 2021. In 2020, paint layers replicas of frescos were prepared in vitro by buon and lime fresco painting techniques with blue smalt and yellow ochre pigments. The samples were treated with the three consolidants and aged at ambient conditions. In 2023, the authors repeated the analysis to assess and compare the three-year effect of the laboratory-prepared nanolime on the paint layers with regard to the commercial nanolime and acrylic resin. The analytical setup comprised photography, scanning electron microscopy coupled with energy dispersive x-ray spectroscopy, and colorimetry or spectrophotometry. Monitored parameters were the impact of the treatments on the paint layer morphology and on the colour. After three years, the presence of all products is still detected on the paint surface, where they maintain their effects on the paint layer morphology. Aesthetical changes that occurred immediately after the treatment have maintained a relatively constant value over the course of time.