Estudio de tratamientos de limpieza sobre revestimientos de yeso policromados

Resumo

The work presented includes a comparative study of cleaning treatments for polychrome plaster coatings.The study’s importance lies in the amount of this type of work in the Iberian Peninsula, being especiallyrelevant those from medieval times, called plasterwork or carved stucco (Spanish term “yesería”). Theconservation and restoration of these artworks goes through a series of key alterations for theirpreservation, especially the liming and repolychromy made in glue tempera and oil. Given a lack ofstudies focused on the removal of this type of alterations, this paper focuses on selecting a series oftreatments, both physical, such as the scalpel or Papeta AB57, even chemical, with the application ofdifferent gels, such as polyacrylic acids, complex polysaccharides, or cellulose ethers. The effectivenessof these treatments has been assessed based on the creation and comparison of photogrammetric models,a methodology that is easy to apply, and harmless to the piece of work, which allows the assess atreatment’s effectiveness at a qualitative (visual) and quantitative level. The results obtained throughphotogrammetry allow us to establish that the most effective treatments to eliminate limewash andrepolychromy of glue tempera are gels made with complex polysaccharides and cellulose ethers, with deionized water. However, polyacrylic acid gels and complex polysaccharides with White Spirit solventand Acetone have been effective in oil repolychromy.