Fig. 6From: A study of the deterioration of aged parchment marked with laboratory iron gall inks using FTIR-ATR spectroscopy and micro hot tableFTIR spectra of standard compounds and formulations; a parchment; b collagen; c gallic acid; d gum arabic; e iron (II) sulfate heptahydrate; f laboratory iron gall ink from mixing iron (II) sulfate heptahydrate with gallic acid (formulation LIG); g laboratory iron gall ink from mixing iron (II) sulfate heptahydrate with gallic acid and gum arabic (LIGG). All spectra shown in absorbance mode. Spectrum a recorded in ATR-FTIR mode; spectrum b recorded on films of the corresponding material on silicon wafer in transmission mode; spectra c–g recorded from KBr samples in transmission mode. Spectrum d is shown off scale in the 3600–3000 cm−1 areaBack to article page