## 3 Results
### Control Specim Analysis and Experimental Data Processing
#### 3.2.1 Type 1 Test Specimens  
1. Physicochemical studies
* **Measurement of the contact angle (CA) on the specimens' surfaces. ** Contact angle measurements were performed in duplicate to evaluate the hydrophobic or hydrophilic behavior of the different fillers under various conditions. This parameter is relevant to the assessment of efficiency and compatibility, as it reflects the wettability of each putty. Furthermore, \"contact angle (CA) measurements may provide quantitative information on the interfacial energy between a liquid drop and a solid surface\" [38; 39]. The procedure for measuring the contact angle [40; 41] followed that established in UNE-EN 15802 [42], which specifies a method for determining the wettability of porous inorganic materials by measuring the contact angle of a water droplet. A 5 \(\upmu\)L drop of distilled water was carefully deposited on the surface using a micropipette, and a photograph was taken 5 s after deposition to determine the contact angle. This value was used to assess the surface wettability of each sample. **Results**. For the interpretation of the results, surface behavior must be taken into account, which can be classified according to the contact angle. A low contact angle (<90\({}^{\circ}\)) indicates that a surface is hydrophilic, favoring the absorption, adhesion, and penetration of the material. A high contact angle (\(\geq\)90\({}^{\circ}\)) indicates that a material is hydrophobic. Materials M9, M8, M7, M6, and M5 presented contact angles of less than 90\({}^{\circ}\), indicating that they have hydrophilic surfaces that favor the adhesion of aqueous materials such as clays with rabbit glue. The contact angle values obtained for each material are shown in Figure 6. M4 absorbed water immediately, and its content of wood chips allowed for very rapid drying; this sudden water absorption could lead to cracking. In general, the hydrophilic nature of these putties may enhance cohesion between layers and help to reduce delamination or separation issues. In contrast, materials M3, M2, and M1 exhibited low contact angles (\(\geq\)90\({}^{\circ}\)), indicating that they have hydrophobic surfaces over which water does not spread well, making it difficult for aqueous materials to adhere. Their hydrophobicity means  
Figure 5: Kiviat diagrams showing comparative evaluation of the materials. Each axis represents a normalized score from 0 to 100, enabling a visual comparison of each material’s performance across different intervention stages. **(a)** Preparation and application behavior, evaluated through four parameters: preparation difficulty, complexity in application and modeling, textural adaptation, and workability. **(b)** Post-drying behavior, including dimensional stability, surface cohesion, adherence to the wooden substrate, and visual integration. Source: DorART Project (own data) 2025, visualized as Radar Chart [37]. that they may require surface treatment, such as sanding or priming, to improve their interaction with water-based gilding. * **Analysis of the average pH evolution on the material surfaces over the test cycles. ** This study reveals different trends for each material and provides an assessment of their chemical stability. Measurements were carried out using the Horiba(r) scientific compact pH meter LAQUAtwin-pH-11 (Horiba(r) Ltd., Kyoto, Japan) with Agarose Basic A8963,0100 PanReac AppliChem(r) (AppliChem GmbH, Darmstadt, Germany)plugs, a polysaccharide that forms a thermoreversible gel: \"(\(\ldots\)) _Gelation occurs at temperatures below 40 \({}^{\circ}\)C, whereas the melting temperature appears to be 90 \({}^{\circ}\)C_\" [43]. Agarose plugs, used to measure the pH of the surfaces, were prepared in a 4% solution in water, with double-boiling in a microwave, according to the method proposed by [PERSON], from the Getty Conservation Institute [44]. **Results**.