Visualising iron gall ink underdrawings in sixteenth century paintings in-situ by micro-XRF scanning (MA-XRF) and LED-excited IRR (LEDE-IRR)

Heritage Science

Table 3 Overview about gained results

Object	Microscopy	MA-XRF	LEDE-IRR	SEM/EDX
Holbein the Elder “Tree of Jesse” (Inv. No. HM 6)	Brown-black, translucent, no particles visible	Fe, Cu, Zn	Lines with varying properties, either invisible or clearly visible at 1550 nm	Fe, Cu, Zn, Al
Holbein the Elder “Bearing of the Cross” (Inv. No. HM 15)	Brown-black, translucent, black particles visible	Fe, Cu, Zn	Visible up to 1550 nm with only a slightly enhanced transparency	Fe, Cu, Zn, Al
Cima da Conegliano “Virgin and Child” (Inv. No. 852)	Type 1: Brown-black, translucent, no particles visible. Fine drying cracks in thickly applied strokes	Fe, Zn	Visible up to 1550 nm with only a slightly enhanced transparency	Fe, Zn, Al, K, Mg, S
Cima da Conegliano “Virgin and Child” (Inv. No. 852)	Type 2: Green(?)/ black, thinly applied lines containing a noticeable amount of black particles	Fe, Zn	Visible up to 1550 nm	Fe, Zn, Al, K, Mg, S, (Cu)