## 4 Conclusions  
The imaging approach of MA-XRF employed in this study allowed to obtain information regarding the materials and techniques used by [PERSON] in his _Entombment of Christ_. With a degree of uncertainty due to the technique itself, traditional materials were determined or hypothesised by XRF. These include azurite, ultramarine, lead-white, vermilion, Cu-based green, Fe oxides/hydroxides (earth/oches), lead-tin yellow, and gold (in thin lines in halos). The detection of Ca traces associated with some areas possibly suggests the use of dyes or lakes in which a calco-potassic glass, present as a drier/sicative, is consistent with the Flemish technique during those times. Although committed by the [PERSON]'s family, this result may also in principle confirm the Flemish production of the painting and exclude the possibility that it was painted in Florence during the artists' journey to Italy, as the Italian glass used for this purpose were Mn-rich rather than Ca-rich. As it has been demonstrated also in this study, MA-XRF allows the non-invasive mapping of the distribution of the different painting materials in sufficient detail, but at the same time it is true that unfortunately it lacks the specificity for a comprehensive characterisation of all materials. It is indeed highly recommended to combine, when available, other analytical methods for an accurate identification of the compounds. However, MA-XRF is undoubtedly a powerful technique which is a source of relevant information, especially when employed as an early non-invasive and non-destructive analytical method acting as a guide for a subsequent more accurate scientific analysis. Figure 6: Detail of [PERSON] and [PERSON], with relative Pb(L\(\alpha\)), Hg(L\(\alpha\)), Fe(K\(\alpha\)), Cu(K\(\alpha\)), Sn(L\(\alpha\)), and Au (L\(\alpha\)) XRF maps. The grey scale in the Cu map is edited to enhance the distribution in flesh tones and hair. K(K\(\alpha\)), Hg(L\(\alpha\)), Sn(L\(\alpha\)) and Ca(K\(\alpha\)) XRF maps. Measuring conditions (both areas): scanning speed 2 mm/s, pixel size 250 \(\upmu\)m. Figure S2: Detail of the Virgin, with relative Pb(L\(\alpha\)), Fe(K\(\alpha\)), Au(L\(\alpha\)), Hg(L\(\alpha\)), and Zn(K\(\alpha\)) XRF maps. Figure S3: Detail of the city in the far right of the background, with relative Hg(L\(\alpha\)), Fe(K\(\alpha\)), Ca(K\(\alpha\)), Cu(K\(\alpha\)), and Sn(L\(\alpha\)) XRF maps. Figure S4: Detail of Magdalene, with relative Pb(L\(\alpha\)), Fe(K\(\alpha\)), Hg(L\(\alpha\)), Sn(L\(\alpha\)), Zn(K\(\alpha\)) and Ca(K\(\alpha\)) XRF maps. Figure S5: Detail of the upper left landscape, with relative Ca(L\(\alpha\)), Fe(K\(\alpha\)), Pb(L\(\alpha\)) and Zn(K\(\alpha\)) XRF maps. Figure S6: Detail of the eyes of [PERSON], with relative Fe(K\(\alpha\)), Hg(K\(\alpha\)), Pb(L\(\alpha\)) and Cu(K\(\alpha\)) XRF maps. Measuring conditions: scanning speed 2 mm/s, pixel size 250 \(\upmu\)m.  
Conceptualization, A.M., C.R., L.C. ; methodology, F.T., L.G., P.A.M.; software, F.T., C.C., L.C. ; validation, P.A.M.; formal analysis, A.M., C.R. ; investigation, A.M., C.R. ; resources, F.T., L.G., P.A.M.; data curation, F.T., C.C., L.C. ; writing--original draft preparation, A.M.; writing--review and editing, A.M., L.C., C.R., L.G. ; visualization, A.M., C.R., L.C. ; supervision, F.T., P.A.M.; project administration, F.T. All authors have read and agreed to the published version of the manuscript. This research received no external funding. The authors are grateful to the _Opificio delle Pietre Dure_ and the _Gallierie degli Uffizi_ for allowing this study. In particular, [PERSON], [PERSON], [PERSON], [PERSON] (OPD), [PERSON] and [PERSON] (Uffizi) are gratefully acknowledged. Authors warmly thank [PERSON] for her contribution to the MA-XRF software. Thanks are also due to [PERSON] for his invaluable technical support and to [PERSON] for his helpful suggestions. The authors declare no conflict of interest. References  
[PERSON] MA-XRF for Historical Paintings: State of the Art and Perspective. _Microsc.