Fig. 10
Py-GC/MS chromatogram of sample S11 (likely original and overpainting reds). Py-GC/MS chromatogram obtained upon derivatization with TMAH of sample S11, i.e. multi-layered red paint removed from the sphere’s red flange. Compounds identified in the chromatogram suggest the presence of early enamels, consisting of a mixture of modified drying oils and a diterpenoid resin from the Pinaceae family (palmitic acid methyl ester 74, 87, 43, 55, 41, 143, 75, 57, 69, 227, 270; stearic acid methyl ester 74, 87, 43, 55, 75, 143, 41, 57, 69, 298; azelaic acid dimethyl ester 152, 55, 74, 83, 111, 59, 143, 185, 69, 41, 217; methyl 6-dehydrodehydroabietate 237, 197, 41, 43, 195, 155, 141, 165, 179, 312; tetradehydroabietic acid, 7-methoxy-, methyl ester 342, 267, 282, 227, 343, 268, 228, 216, 251, 126; 15-methoxydehydroabietic acid, methyl ester 329, 330, 269, 313, 73, 344, 43, 107, 145, 314, 344; 7,15-dimethoxytetradehydroabietic acid, methyl ester 372, 297, 340, 313, 73, 357, 141, 341, 373, 257)