Elementos para uma arqueologia de misturas de cera-resina usadas como adesivos em Talha e Escultura policromada

Abstract

A mixture of beeswax and Dammar resin (in a ratio of 7 parts to 2 parts, respectively) prepared as an adhesive, was profusely used for fixing water gilding and tempera coatings on polychrome sculptures, in Portugal, in the second half of the twentieth century. This practice was the result of a conservation technology transfer that took place throughout northern Europe, namely throughout education and training of young restorers from abroad at Institut Royal du Patrimoine Artistique in Brussels. This type of treatment was challenged in the 1970’s. This paper presents the methodology used (from an archaeological perspective) to find again these substances on sculptures which have been impregnated with them, and show until which point it is possible to detect both wax and resin in the paint layers. The results obtained by micro Fourier transform infrared spectroscopy, and Pyrolysis-Gas Chromatography-Mass Spectrometry proved difficult to put in evidence the presence of the Dammar resin; a limit which is not without consequences for the historic and conservation assessment of our heritage.