Research describes a new, less toxic method for removing varnish from artworks using ionic liquids than those used in the art restoration business currently.
Cleaning methods for conserving and restoring art usually involve the use of volatile organic solvents that van be harmful to both health and the environment. Scientists in Portugal investigated the use of ionic liquids as an alternative because of their low toxicity, their high viscosity (which inhibits penetration of the paint layers) and their miscibility with water and alcohol for the safer clearance of the varnish remover compared to the traditional organic solvents.
The scientists investigated a series of ionic liquids for the removal of different types of varnish from mocked-up paintings and showed that they removed the varnishes effectively using FTIR microspectroscopy. They also investigated the clearance of the ionic liquids using water and a water/ethanol mixture, and showed that there were no detectable residues.
The scientists tested their method on a real-life painting made in oil on canvas, and showed that it was effective at removing a dark, naturally-aged varnish from the surface of the painting without damaging the paint layers.