Removal of Non-original Transparent Coatings on a Dutch Lacquer Cabinet

Abstract

This paper describes the investigation into the possibilities of removing non-original coatings on a Dutch late seventeenth-century lacquer cabinet. The secondary coatings show various degradation phenomena such as alligatoring, discolouration and craquelure, which have significantly changed the appearance of the original decoration. The aim was to find out if the degraded secondary coatings could be removed whilst preserving the original layers and to choose the most suitable method. Practical tests were carried out to remove thick oil-resin varnish from dammar varnish. The dammar varnish, also a secondary layer, was preserved because it retained good optical properties and serves as a protection for the original layers. The most suitable method for removing the oil-resin varnish proved to be a buffered aqueous solution, modified with the enzyme Lipase type VII and applied in xanthan gum gel or Evolon®, in combination with binary solvent mixtures for removing the softened varnish and rinsing the surface. The visibility and aesthetic appearance of the original decoration increased significantly.