DYES AND DYEING - Archaeological Chemistry - page 376

the dye; when the water evaporates, kermes precipitates as a powdery
residue. The coloring matter in kermes is the organic compound kermesic acid
(Schweppe and Runge 1986; Dimroth and Scheurer 1913).
Cochineal , also derived from the bodies of insects, was known for many
centuries to the pre-Columbian inhabitants of the Americas. Its native habitat
seems to have been Mexico, although there is evidence that it was also used
for dyeing in Peru during the Inca period (Dahlgren 1990). Cochineal was
apparently unknown outside the American continent until the beginning of
the sixteenth century, when, following the Spanish conquest of Mexico, it
was brought to Europe. It has been suggested, however, that a red dye
similar to cochineal may have been derived from a variety of insects native
to the Ararat valley in Turkey (Verhecken and Wouters 1988-1989). In ancient
Mexico cochineal was extracted from the dried bodies of Coccus cacti , insects
that live on the cactus plant Nopalea cochenillifera . To obtain the dye, the
insects were first collected and then killed by one of three methods: immers-
ing them in scalding water, wrapping them in a bag and exposing the bag
to the heat of the sun, or placing the bag in a hot oven. The dye, which is
soluble, was then extracted from the dead insects by immersing them in
water. After filtering out the exhausted solids from the solution, the water
was evaporated and the dye was obtained as a red powder. The coloring
matter in cochineal is the organic compound carminic acid (Schweppe and
Runge 1986).
Lac is derived from lac resin , the hardened secretion of the lac insect, the
only known resin of animal origin. The lac insect, Kerria lacca , formerly
known as Laccifer lacca , is a natural parasite of a variety of trees in large areas
of southern Asia. Three different products are derived from lac resin: lac dye ,
lac wax , and shellac . To obtain the lac resin, twigs encrusted with the
secretion of the insects are cut down from the trees, then the incrustation is
separated from the twigs, washed with water, and filtered. The wax and
shellac, which are insoluble in water, remain as a solid residue of the filtra-
tion, while the soluble red dye (lac) is obtained as a powder when the water
from the filtered solution is evaporated. The coloring matter in lac dye is an
organic compound known as laccaic acid .
Yellow Dyes
A number of yellow dyes were known in antiquity; weld and saffron seem to
have been the most widely used, but barberry root , turmeric , Persian berries ,
and safflower have also been identified in ancient fibers. Weld , probably the
oldest European-known yellow dye, is derived from the herbaceous plant
Roseda luteola , which is indigenous to central Europe. The dye is distributed
throughout the entire plant, although it is concentrated in the upper