This painting is in oil paint on canvas measuring 647 x 535 mm (figs.1–3). The plain woven, linen canvas has approximately 14 threads per centimetre each way. It has cusping on all edges.1 Marks left by the original stretcher indicate that it was a simple rectangle with bars about 40 mm (1 ½ in) wide.
The ground is a thick, opaque coat of reddish brown paint (figs.4–5). There is no priming. No underdrawing is apparent (fig.6).
The thin, dense paint was applied in layers in the background and wet-in-wet elsewhere with highlights and glazes added last (figs.7–10). The pigments are finely ground with the exception of orpiment, which was used to great effect for the highlights of the wing and body of the bird suspended at the top of the picture; its large, crystalline particles catch the light and illustrate the reason for the literal name ‘gold pigment’ (figs.11–12).2
1. Cusping is the name for arcs of in-plane distortion in the weave at the edge of a canvas caused when it was first held taut with tacks or cords for priming.
2. Identification of pigments was carried out with analytical microscopy by Rica Jones and Kate Stonor, followed by EDX (energy-dispersive X-ray analysis) by Dr Joyce Townsend.