Preliminary investigation of various old geomaterials treated with hydrophobic pellicle

The purpose of this article is to evaluate the aesthetic and chromatic impact of hydrophobic treatments carried out on a series of old geomaterials, dating back to the XVII and XIX centuries. The materials in question have been utilized in the construction of two historic monuments. Throughout the evaluation proceedings regarding the state of conservation of the monuments in question, a number of porous surfaces were identified, such as calcareous rock and ornamental terracotta. The aim of the article is to evaluate the hydrophobic degree obtained by applying certain pellicles, in keeping with the modern principles of scientific conservation. During the experiments, an array of different commercially available hydrophobic additives was used. The tests were performed in laboratory conditions, with the purpose of presenting the chromatic interaction between surface and product. The main techniques used for the analysis during the experiments were: CIE L* a* b*, OM and exposure to UV radiation in laboratory conditions. The results obtained are analyzed and discussed, with the purpose of evaluating the efficiency of hydrophobic solutions, taking into consideration the chromatic deviation, as compared to exposure to UV radiation. © 2016 Wiley Periodicals, Inc. Col Res Appl, 2016