## 1 Introduction
However, there is a fourth and crucial point to consider: EM techniques are by far the safest technologies available for achieving a comprehensive understanding of an artifact without compromising its integrity. Figure 2[20] offers a clear example of what is meant by \"different levels of knowledge\". It shows the distribution of chemical elements derived from macroscopic X-ray fluorescence (MA-XRF) analysis alongside their crystalline phases, identified using macroscopic X-ray powder diffraction (MA-XRPD). Figure 2: Elemental and relative phase maps. The techniques applied are MA-XRF and MA-XRPD. Credit [PERSON] et al. [20]. Licensed under Creative Commons [[http://creativecommons.org/licenses/by/4.0/](http://creativecommons.org/licenses/by/4.0/)]([http://creativecommons.org/licenses/by/4.0/](http://creativecommons.org/licenses/by/4.0/)) (accessed on 20 November 2024). The Creative Commons Public Domain Dedication waiver applies to this picture: [[https://creativecommons.org](https://creativecommons.org)]([https://creativecommons.org](https://creativecommons.org)) (accessed on 20 November 2024). No changes were made to the figure but to capture. According to the reviewed literature, current state-of-the-art developments in diagnostic techniques are primarily associated with studies and research focused on paintings. Table 3 summarizes the most established electromagnetic (EM) techniques currently used in the field, along with their applications and key references. For clarity, only the principal techniques are listed without detailing all their variations--for example, X-ray diffraction includes both macro and micro X-ray powder diffraction. As is immediately evident, the majority of scientific work has concentrated on paintings across a wide range of substrates and historical periods, often involving renowned artists and masterpieces, from [PERSON] to [PERSON] and [PERSON]. Particular emphasis has been placed on pigment analysis, especially in identifying blue and yellow pigments, with somewhat less focus on red and green. This dominance of studies on paintings likely stems from a factor discussed in the introduction: the immense economic value and global significance of certain CH artifacts. Additionally, cultural heritage legislation and museum policies, which frequently restrict the relocation of masterpieces--have driven the development of portable instrumentation capable of performing in situ diagnostics [21; 22; 23; 24; 25; 26; 27]. Less attention has been devoted to jewelry [67] and glass [59], with slightly more focus given to coins and metal objects, which can shed light on specific social and historical processes [38; 41; 68; 69]. Modern and Contemporary Art represents a distinct case [62; 63; 64; 65; 66; 67; 68; 69; 70; 71; 72; 73; 74; 75; 76; 77; 78; 79; 80; 81]. Museum directors are increasingly advocating for scientific solutions in the preservation of Modern--and especially Contemporary Art, as the artifacts from these periods are inherently perishable due to the nature of the materials used. Despite ongoing appeals and reminders from museums and gallery owners, there remains a significant gap in the scientific literature on this subject. Most available studies and publications are limited to pigment analysis and cleaning techniques. To conclude this introduction, the review emphasizes the lack of standardized practices for the application of CH and EM techniques across various contexts. Despite differences in methods, regulations, and limitations, there are no universally accepted guidelines or best practices, and much of the relevant information is dispersed across numerous sources. Obtaining reliable, application-specific data remains a challenge. As [PERSON] noted [82], unlike medical imaging, heritage imaging lacks comprehensive datasets and