Table 1 Summary of the analysis (see “Instrumentation”) of samples from Whaam! (Tate T00897), derived from several analytical campaigns
Paint colour | SEM/EDXa | FTIR (transmission) | Polymeric components (GCMS) | Polymeric components (PyGCMS) | Inferred composition | ||
|---|---|---|---|---|---|---|---|
Binding media | Pigment | Otherb | |||||
White (priming) | Ti, Ca, S, Si, Na | Proteinaceous material Oil-modified alkyd resin | Titanium dioxide (TiO2) | Calcium sulphate tetrahydrate (CaSO4·4H2O) | Phthalic anhydride | – | Animal glue sizing, and on top an oil-modified alkyd resin medium mixed with titanium white (PW6), gypsum and silica as extenders |
Blue paint (Ben-Day dots) | Na, Al, Si, S, Ca, Mg, K, Ti | Oil | Ultramarine blue (Na8Al6Si6O24–Sx) Titanium dioxide (TiO2) | Calcium carbonate (CaCO3) | – | – | Oil medium with synthetic ultramarine blue (PB29) Titanium white (PW6), gypsum and silica are likely to originate from the preparation layer |
Red paint (Ben-Day dots) | – | Oil | – | Barium sulphate (BaSO4) Possible metal soaps | – | – | Oil medium with probable cadmium red pigment (associated with barium sulphate) |
Yellow paint (except speech bubble area) | Cr, Pb, Zn | nBMAc | Lead chromate | Wax Zinc stearate | Wax Traces of oil fatty acids and diacids | nBMAc | Acrylic solution medium (Magna), with traces of oil, mixed with lead chromate yellow PbCrO4 (PY34) Zn stearate may be an additive or formed from CdZnS (cadmium zinc sulphide lemon yellow) pigment present at minor levels (PY35) |
Red paint | Cd, S, Se | nBMA | – | Wax | Wax Traces of oil fatty acids and diacids | nBMA | Acrylic solution medium (Magna), with traces of oil, mixed with cadmium red Cd (S, Se) (PR108) |
Black paint | Fe, S | nBMA | – | Wax | Wax Traces of oil fatty acids and diacids | nBMA | Acrylic solution medium (Magna), with traces of oil, mixed with Mars (iron oxide) black (PBk11) |
Yellow paint (speech bubble upper layer) | Cd, Zn, S | Oil oxidised | – | Magnesium sulphate heptahydrate oxalate salts | Wax Traces of oil fatty acids and diacids | – | Water sensitive oil paint with probable cadmium zinc sulphide (lemon) yellow (PY35) and a source of magnesium as extender |
Yellow paint (speech bubble underlayer) | Cr, Pb, Zn | nBMA | Lead chromate | Wax Zinc stearate | Wax Traces of oil fatty acids and diacids | – | Acrylic solution medium (Magna), with traces of oil, mixed with lead chromate yellow PbCrO4 (PY34) Not water sensitive. Zn stearate may be an additive or formed from CdZnS (cadmium zinc sulphide lemon yellow) pigment present at minor levels (PY35) |