Page 18 - Copper and Bronze in Art: Corrosion, Colorants, Getty Museum Conservation, By David Scott

Introduction

Bronze vessels that have been interred under the earth a thousand years
appear pure green the colour of kingfisher feathers... those that have
been immersed in water a thousand years are pure emerald in colour
with a jade-like lustre. Those that have not been immersed as long as
a thousand years are emerald green but lack the lustre... those that
have been transmitted down from antiquity, not under water or earth
but through the hands of men, have the colour of purple cloth and a
red mottling like sand, which protrudes when excessive, and looks like
first-quality cinnabar. When boiled in a pan of hot water the mottling
becomes more pronounced. —ZYIAO X I G U 1

l^^^uring the Song dynasty (960 -1279) , when the connoisseur
Zhao Xigu was writing, ancient Chinese bronzes were already being excavated and studied.
Indeed, these antecedents of Chinese art were a source of inspiration and fascination long
before an interest in the appearance of ancient bronzes arose in the West. This early apprecia­
tion of patinas is shown by the fact that Zhao Xigu was prepared to undertake experimenal work
on them, boiling them in water to observe the slightest reaction or change in appearance.
It is this spirit of empirical inquiry that forms the basis for this book, which seeks to extend
this time-honored tradition by reviewing the existing literature on copper and copper com­
pounds, especially as it relates to art and archaeology. The chapters that follow explore the
chemical processes involved in the development of patina and corrosion products in various