Fernissa på papper - en komparativ studie mellan PVOH-borax och lösningsmedelsbad vid lackborttagning på papper

Abstract

The main purpose of this study is to investigate the usage of high viscosity polymeric hydrogels in varnish removal on paper objects, for conservation purposes. Varnishing paper artefacts was a common practice between the 18th and 20th century. However, the procedure has resulted in degradation and discoloration of paper artefacts, which usually results in the removal of the varnish by conservators. The study aims to investigate the solvent-based poly(vinyl alcohol) (PVA) and borate gel as an alternative for removing shellac varnish on paper artefacts. Different solvent-based gels are frequently used in fine arts conservation but are not commonly used in paper conservation. Traditional conservation methods with solvent baths may have negative consequences in terms on the effect on the paper substrate. The hydrogel PVA-borax will be compared to traditional solvent baths commonly used in paper conservation. The study includes a disciplinary literature study of PVA-borax usage for cleaning works of art and the historical usage of varnish on paper objects. Artificial aging of shellac samples are carried out in order to provide sufficient materials and samples for analysis. The chosen analysis methods are Fourier-transform Infrared Spectroscopy (FTIR) and Ultraviolet (UV) Fluorescence imaging, which both can be used to indicate the presence of shellac residues left after removal. The FTIR analysis shows that PVA-borax is an insufficient substrate for removal of varnish on paper samples due to the low percentage of solvents of the total moisture content carried out in the gel. However, a case study on a varnished wall map shows that PVA-borax gel sufficiently removes aged varnish from the paper substrate. Further studies are needed to analyse the gels sufficiency as a varnish removal agent on paper substrates.