*3.5. Black*

The black paint from the lower pennants of *Man-Eater* showed two layers in the cross section, in addition to extensive rusting. The aluminum layer was not seen in the cross section but observed during treatment. This points to consistent surface preparation of the metal before applying any paint. Raman analysis of the layers proved difficult due to overwhelming fluorescence. Mapping with SEM-EDS was more fruitful here and confirmed XRF analysis, where Layer 1 was rich in Ca and P, which indicates the presence of bone black (P.Bk. 9; C.I. 77267). Bone black is defined as a carbonized product of collagen mixed with hydroxyapatite (Ca5(PO4)3), and the latter is the source of Ca and P in the SEM-EDS and XRF [45]. Layer 2 did not show the presence of these secondary constituents and can indicate a carbonaceous black not derived from bone matter. The black-painted shapes on the maquette also had only two layers. Fluorescence was not problematic in this instance, and Raman analysis of Layers 1 and 2 indicated the presence of a carbon-based black in both layers, with D and G bands at 1324 and 1597 cm−1, respectively [46]. The D band is indicative of disorder in the crystal structure of carbonaceous blacks, while the G band arises from C–C stretching [47]. While both layers are rich with large particles of Ca that were identified as CaCO3 by Raman spectroscopy (156, 238, 714, 1090 cm<sup>−</sup>1), only Layer 1 is rich in aluminosilicates based on SEM-EDS. Finally, Layer 2 interestingly showed the presence of Prussian blue by Raman spectroscopy with weak but readily identifiable 1Ag ν(CN) stretching vibration at 2160 cm−<sup>1</sup> and the Eg ν(CN) stretching vibration at 2090 cm−1. Curiously, XRF spectra indicate that the rods were painted with a bone black, where hydroxyapatite was detected by the presence of phosphorous, unlike the pennants.
