Page 275 - Copper and Bronze in Art: Corrosion, Colorants, Getty Museum Conservation, By David Scott

Geographic distribution This remarkable blue pigment first appears in wall paintings
of Egyptian blue around the Egyptian Fifth Dynasty (2465- 2323 B.C.E.). It con­
tinued to be used in Egypt through the Late Dynastic period
(1085- 343 B.C.E.), becoming less common during the Greek (332- 30 B.C.E.) and Roman peri­
ods (30 B.C.E.-395 C E . ) (Noll 1979, i98i). It was still in use until the construction of monuments
during the reign of Caesar Tiberius (14- 37 C E . ) . Egyptian blue was used extensively in wall
paintings at Pompeii, and the Etruscans also used the pigment frequently.
Less is known about the use of the pigment in ancient Mesopotamia and Persia, although
it was undoubtedly available in such centers as Nimrud and Nineveh. Granger (1933) identi­
fied Egyptian blue from the Assyrian palace of Til Barsip, dating to about 1000 - 612 B.C.E., while
Stodulski, Farrell, and Newman (i984) found Egyptian blue and azurite used in reliefs at the
Persian sites of Persepolis and Pasargade, dating from the sixth to fifth century B.C.E.
The pigment has not been reported from India or from central or eastern Asia, where the
earliest wall paintings date from around the first century B.C.E. (Riederer 1997). Only natural
ultramarine, azurite, and indigo have been found as colorants in that part of the world, sug­
gesting that those cultures may not have had a particular need to import Egyptian blue.
The most remarkable identification of Egyptian blue pigment is from the far north of Nor­
way, within the arctic circle, where Rosenquist (1959) found it as blue pigment on a shield from
graves of the Bo people of that region that date to about 250.

Lost and found secrets By the fourth century the secrets of Egyptian blue manufacture
of Egyptian blue were completely lost and remained a mystery for over fifteen
hundred years until scientists of the early nineteenth century
began to unravel the story of the pigment's identity and methods of its fabrication. One of the
first detailed investigations of that time was carried out by Sir Humphry Davy on blue pigments
found in the baths of Titus and Livia in Rome, as well as in the ruins of Pompeii. Through chem­
ical experiment, Davy deduced that Egyptian blue was a copper frit. He writes:

A quantity of the colour was fused for half an hour with twice its weight of hydrate of
potasse: the mass which was bluish-green was treated by muriatic acid in the manner usu­
ally employed for the analysis of siliceous stones, when it afforded a quantity of silica equal
to more than A of its weight. The colouring matter readily dissolved in solution of ammo­
3
nia, to which it gave a bright blue tint, and it proved to be oxide of copper. The residuum
afforded a considerable quantity of alumine, and a small quantity of lime. (Davy 1815:99)

Davy was aware of the first-century B.C.E. writings of Vitruvius, who referred to Egyptian
blue, which he called "caerulaeum," as the color commonly used in wall painting. Davy also
knew that the pigment was made in Vitruvius's time at Pozzuoli, Italy, and that the method of

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