Fig. 9

OCT depth profiles of a series of paint films of pure pigments, and pigment mixtures based on sample x34 from Homer’s belt (78 vol% smalt/glass, 10 vol% red earth, 10 vol% yellow earth, 2 vol% bone black), showing the effect of a substantial amount of smalt on the translucency and surface topography of the paint: pure smalt paint (2.66 wt% CoO) (a), pure madder paint (b), pure yellow earth paint (c), pigment mixture 34 with smalt (2.66 wt% CoO) (d), pigment mixture 34 with colorless potash glass (e), pigment mixture 34 with no smalt added (f). Note that the depth axis of a–f assumes that the refractive index is equal to 1 for all components within the sample. Therefore is represents the optical distance, and not the exact geometrical distance