Page 197 - Copper and Bronze in Art: Corrosion, Colorants, Getty Museum Conservation, By David Scott

Three thin sections from a fifteenth-century
P L A T E 1 6
Chinese cloisonné enameled vessel: , viewed under
A
crossed polars, showing cuprite crystals in the enamel;
B, viewed under partially crossed polars; and c, viewed
16A
under standard illumination, showing blue dichroism of
the cuprite crystals (all at magnification χ270) .
P L A T E 17 Thymiaterion (incense burner) in the Form
of a Comic Actor Seated on an Altar, Roman, first half of
C
first century . E . Bronze, : 23.2 cm; w (base): 13.3 cm.
H
Shown after mechanical conservation cleaning, this sculp­
ture reveals a patina that contains both chalcocite and
tenorite over a thin cuprite layer. The figure is hollow
cast, and the altar is pierced underneath for ventilation.
When incense was burned inside the figure, the smoke
would have emerged through the actor's mouth. The pres­
ence of tenorite is possible because of this heating. Collec­
tions of the J. Paul Getty Museum (87.AC.143).

P L A T E 1 8 Cut malachite from Arizona, showing typical
banded morphology, a common feature of malachite
formation.

16B

I 6 C

180