Page 351 - Copper and Bronze in Art: Corrosion, Colorants, Getty Museum Conservation, By David Scott

TWO D E T A I L E D S T U D I E S OF PATINA AN D C O R R O S I O N

Roman bronzes The author made a detailed study of the natural patinas of four
bronzes that came on the art market in 1984, finding evidence
that could be used to support the archaeological association of these sculptures (Scott 1994a).
This group consists of three objects in the collections of the J. Paul Getty Museum —a Roman
bronze identified as a statuette of Roma (Rome) or Virtus (valor), a relief fragment of two men
(the "Togati bronze")/ and a statuette of Ceres (the Greek Demeter) or Juno (the Greek Hera) —
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and a fourth piece, Victory with Cornucopia (winged Nike), at the Cleveland Museum of Art. All
four sculptures are assigned a date between 40 and 68 C.E., and all are made by the lost-wax pro­
cess in leaded tin bronze with cast-on additions. Further details of their X-radiography and cast­
ing are reported by Scott and Podany (1990).
The statuette of Roma, or Virtus, is shown in PLATE 71. This bronze statuette, which may
originally have been a chariot attachment, is shown wearing a short tunic unfastened on the
right shoulder and an Attic helmet with a visor and crest. Roma is shown standing in this dress
on coinage from the time of the Roman Emperor Galba (reigned 68- 69 C.E.) (Herrmann 1988).
An unusual hexagonal network in the detail on the reverse surface of the figure, near a large
opening in the back, is shown in PLATE 72. Each hexagon is about 1 mm across, and the network
is clearly visible in many areas of this surface. This hexagonal structure is rarely seen in corro­
sion layers, and no satisfactory explanation has yet been offered for its presence.
In the Togati bronze, shown in PLATE 73, the figures are dressed for a patrician ceremony.
The details of their dress and clothing suggest first-century comparisons, as does the hair on
the older-looking figure; it is brushed forward on the neck, as in portraits of Caligula, Nero,
and their contemporaries (Herrmann 1988). The two figures were cast in one piece, with heads
inverted in the mold so that more gaseous regions toward the top of the casting are in the areas
of the feet, as evidenced by the sculpture being more porous in that region (Podany 1988).
The third piece in the group, not pictured here, is a bronze figure of Ceres or Juno, clad
in a long tunic and mantle. The position of the figure's arms and hands suggests that she once
held an offering dish in her right hand and a scepter in her left. A large, square hole in the back
of the statuette indicates that it was once fastened to another object, perhaps a chariot or a piece
of furniture.
The Victory with Cornucopia, or winged Nike, is shown in PLATE 74. Christman (i989) notes
that the left arm, right leg, and wings were cast separately from the body, which is hollow. This
is very similar to the mode of manufacture of the Roma and Ceres. In an ancient restoration of
the Nike, the wings were repositioned farther apart and lower.
The patina on all four of these bronzes contains the same fibrous malachite that is discussed
in CHAPTER 3 (see PLATES 20 and 21). PLATE 75 is a low-power photomicrograph, revealing
some of the features of the surface corrosion of the Togati. In areas where the surface has been

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