Fig. 3From: An enhanced procedure for the analysis of organic binders in Pompeian’s wall paintings from Insula OccidentalisFT-IR peak area (2510 cm−1) at increasing sample amounts (sample S3). For each sample spot deposited on ZnSe window, four spectra were collected and the average peak area, SE and curve equation was calculated. (Filled square) Underlying calcite layer of sample S3; (filled diamond) Paint layer of sample S3. SE, standard errorBack to article page