## 2 Materials and Methods
### Specim Preparation for Aging Tests  
Three types of samples were prepared to analyze different aspects of the materials' behavior. Test Specim 1 focused specifically on evaluating the interaction of the fillers with the wood, particularly in response to its thermo-hygrometric movements. This included analyzing the contact angle to assess surface hydrophobicity and monitoring the pH evolution during aging cycles to detect possible acidification or alkalization processes. Mechanical tests were also conducted, including tensile adhesion tests on wood substrates to evaluate the coating's resistance to detachment, and Shore C hardness measurements to assess the surface's resistance to penetration. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Label** & **Material** & **Binder Family** \\ \hline M1 & Araldite® SV 427-2/HV 427-1. RenPasteTM SV 427-2 /Ren® HV & Synthetic; epoxy resin \\ M2 & Balsite® (CTS Conservation SRL, Altavilla Vicentina, Italy) & (thermosetting) \\ M3 & Epo® 127 (CTS Conservation SRL, Altavilla Vicentina, Italy) & Synthetic; epoxy resin \\ M4 & Vinavi® 59 (Vinavi® S.p.A., Milan, Italy) + sawdust (0.4–0.7 mm) & Synthetic organic polymer; Polyvinyl Acetate; PVAc \\ M5 & Pigmente GmbH \& Co., Aichstetten, Germany) + calcium sulfate, & Synthetic thermoplastic polymer \\ M6 & Beva® 371 (Gustav Berger Original Formula, CTS Conservation & Synthetic thermoplastic polymer \\ SRL, Altavilla Vicentina, Italy) + vermiculite & Synthetic thermoplastic polymer \\ M7 & Paraloid® B-72 (The Dow Chemical Company, Midland, TX, USA) + glass microballoons & Synthetic organic polymer; acrylic \\ M8 & Gypsum (CaSO\({}_{4}\))/deionized water & Inorganic mineral \\ M9 & Rabbit-skin glue/deionized water + 50\% calcium carbonate & Organic hot-melt adhesive \\  & (CaSO\({}_{3}\))/50\% calcium sulfate (CaSO\({}_{4}\)) & \\ \hline \hline \end{tabular} Source: Authors’ own elaboration, DorART Project, 2025, with the collaboration of [PERSON].  
\end{table} 
Table 1: Material selection for experimental evaluation. Test Specim 2 was designed to evaluate the compatibility of the fillers with traditional water-gilded wood surfaces, focusing specifically on the aging of the materials upon contact with gilding performed with an inert base and rabbit glue. The gilding was applied half-burnished and half-unburnished to observe any differential behavior. The interaction between the wood, fillers, and gilt layer was assessed through physical and chemical analyses, including gloss measurements--as an optical indicator of surface texture changes and material loss--and mechanical abrasion tests to determine the fillers' resistance to wear and the impact of this on the stability of the gilded finish. Finally, Test Specim 3 was specifically designed for the mechanical and spectroscopic analysis of the materials, independent of their interaction with the wood. Mechanical tests were performed using a Universal Testing Machine with a load capacity of 100 kN, with controlled displacements applied, following a standardized procedure, to determine the mechanical strength of the system. In addition, chemical characterization was performed using ATR-FTIR spectroscopy, which allowed the identification of functional groups on each material's surface and the analysis of possible chemical changes induced by aging or external agents. To ensure experimental reproducibility and statistical reliability, each material was tested in triplicate, following a standardized protocol that included photographic and dimensional documentation. The test specimens were evaluated for performance, stability, and compatibility through physicochemical and mechanical tests and analyses, including surface examination by optical microscopy. This approach allowed for the identification of consistent trends, minimized the influence of outliers or anomalies, and facilitated a more robust comparative analysis between materials. Due to the exploratory nature of this study and the small sample size (\(n=3\)), statistical significance tests (e.g., ANOVA) were not applied.