Fig. 6 | npj Heritage Science

Fig. 6

From: Non-destructive analyses of iron-polyphenolic complexes for reconstructing iron-gall inks historical recipes

Fig. 6

CW-EPR spectra of iron complexes of commercial tannins. The spectra shown have been initially normalized by the sample weights and just for a better visualization, a further normalization between 0 and 1 has been performed (see also Fig. F.2 in the Supporting Materials). The two vertical dotted lines highlight the inflection points of the two main signals at g ≈ 2 and g ≈ 4.3.

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