Fig. 1

H. Holbein the Elder, “Tree of Jesse” (Inv. No. HM 6), exterior wings, High Altarpiece of the Dominican Church. Left: Visible light image. Right, top down: Cross-section S70 from Jesses’ face in visible light, under UV illumination and backscattered electron image (BSE) in SEM/EDX. Build-up of S70 from bottom to top: (1) chalk priming, (2) iron gall ink underdrawing, (3) paint layer. VIS: CC BY-SA 4.0 Städel Museum, Frankfurt, https://creativecommons.org/licenses/by-sa/4.0/deed.de. S70 VIS, UV and BSE image: ^©Stephanie Dietz, edited by M. Gerken