## 1 Introduction  
\"Global cultural heritage is a valuable asset. It represents a significant industry, generating millions of jobs and billions of euros in revenue annually. However, despite its substantial economic and socio-cultural benefits, relatively little attention is paid to its conservation or to the development of innovative, comprehensive strategies aimed at modernizing the professional field.\" [1] (p. 1). The economic and socio-cultural relevance of Cultural Heritage (CH) is strongly emphasized by the European Commission through European Union (EU) policies on CH [2], as well as by UNESCO [3,4]. In its Competence Framework for Cultural Heritage Management (CHM), UNESCO particularly focuses on the second point mentioned above--the professional skills required to preserve global CH--while also taking into account sustainability goals [5, 6, 7]. The economic value of CH can be considerable. The scientific literature highlights that art consistently outperforms other forms of investment due to its stability and low volatility [8,9]. Table 1 provides a clear example of what is meant by \"tremendous\" economic value. A more comprehensive list of the most expensive paintings ever sold can be found in [10]. [PERSON]'s painting Salvator Mundi is shown in Figure 1. The numbered red spots refer to approximate sample locations during the restoration intervention, which we will discuss in Section 3.1.3. Figure 1: _Salvator Mundi_, oil on walnut panel. [PERSON], c. 1500. Credit [PERSON]. [PERSON] et al. [13]. Licensed under Creative Commons, [[http://creativecommons.org/licenses/by/40/](http://creativecommons.org/licenses/by/40/)]([http://creativecommons.org/licenses/by/40/](http://creativecommons.org/licenses/by/40/)) (accessed on 20 November 2024). The Creative Commons public domain dedication waiver applies to this picture: [[https://creative.co/](https://creative.co/)]([https://creative.co/](https://creative.co/)) (accessed on 20 November 2024). No changes were made to the figure but to capture. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Painting** & **Type of Evaluation** & **Price** & **Ref** \\ \hline Monalisa & Insurance valuation & \$100,000,000 & [11] \\ Salvator Mundi & Price sold & \$450,312,500 & [12] \\ \hline \hline \end{tabular} \({}^{\dagger}\)For what is in our knowledge at the time of writing.  
\end{table} 
Table 1: The two most expensive paintings in terms of the highest \({}^{\ddagger}\) price sold and insurance valuation. Both are [PERSON]’s masterpieces. Table 2 highlights the profound economic and cultural importance of Cultural Heritage (CH), illustrating how its intrinsic value supports conservation initiatives. Heritage assets act as catalysts for tourism, local development, employment, and cultural exchange, thereby justifying continued investment in their preservation. Recognizing this economic significance also fosters the advancement of Non-Destructive Analysis (NDA) techniques, which enable the study of delicate or valuable objects without risking damage [5; 6; 7]. Beyond its economic value, the most significant and powerful attribute of Cultural Heritage (CH) lies in its representation of the deep identity of communities and populations. Within this context, it becomes evident that, regardless of which aspect holds the greatest interest for different stakeholders, the preservation of CH is essential for all. At the same time, this necessity presents a considerable challenge due to the unique variety of materials, forms, and manufacturing processes involved. Any intervention must be conducted without causing damage--or by minimizing risk as much as possible. It is now widely acknowledged that an integrated, multidisciplinary approach is required. Over the past twenty years, this recognition has been pivotal in establishing the importance of a scientific approach, both methodologically and technically, in the field of CH conservation [14; 15; 16]. By the late 1990s, the term _Technical Art History_ began to gain prominence.