Varnish Research at the National Gallery of Art
In research at the National Gallery of Art several avenues were pursued: accelerated aging studies were carried out to investigate the possibility of inhibiting oxidative degradation of natural resin and other varnishes using stabilizing additives, and a search for new, stable, low-molecular-weight resins was conducted. It was found that dammar resin can be stabilized effectively using a hindered amine light stabilizer, but only in an environment free of ultraviolet radiation below 400 nm. In addition, novel low-molecular-weight resins, such as hydrogenated hydrocarbon resins and urea-aldehyde resins, were tested and found to be suitable replacements for traditional varnish materials.