With the advancement of chemistry, scientists found that the coloring matter drawn from the indigoferae plants appears to be chemically identical to the woad plant (isatis tinctoria), grown in Asia and Europe and known as pastel in Languedoc, Provence, and Normandy.(1)   More surprisingly, the blue extract of the indigofera plant differs by only a couple of bromine atoms to the ancient purple (purpura) dye drawn from a shellfish.(2)

Reserved for the Emperor in Imperial Rome, purple was obtained from two species of Mediterranean shellfish, the buccinum (Thais haemastroma) and the purpura (Murex brandaris), where a clear fluid in a gland near the head of the mollusks created, in the former, a darker bluish to red fluid and, in the latter, a brightly colored red-violet one.(3)  As for indigo, the color reveals itself on the cloth through oxidation. Unlike indigo, purple production was both costly and complicated: an once of purple dye required about 250,000 shellfish and the method for preparing the dye, through transmitted in the ancient world, was lost to the West after the fall of Constantinople in 1453 and not recovered until 1856.(4)

Woad was extensively used as a source of blue dye until the introduction of indigo, which proved a better dye.(5)  Like indigo, the coloring matter of woad was traditionally extracted by fermentation. In the case of woad, the plant was soaked in urine, heated by the sun and trampled for a few days.(6)  This lead to harmful and unpleasant industrial emissions.(7)  Additionally, woad drew all the nutrients from the soil and those that farmed it were often migrants that left infertile wastelands behind.

Anne Bissonnette, PhD
Curator
Kent State University Museum

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        (1) Agustí Nieto-Galan, Colouring Textiles: A History of Natural Dyestuffs in Industrial Europe (Dordrecht, Boston, London: Kluwer Academic Publishers, 2001), 28.
        (2) Philip Ball, Bright Earth: Art and the Invention of Color (New York: Farrar, Straus and Giroux, 2001), 201.
        (3) Ball, 199. Nieto-Galan, 30.
        (4) Ball, 199, 200.
        (5) Nieto-Galan, 28. Ball, 203.
        (6) Ball, 202.
        (7) Ibid.

Text Included in the Exhibition

Mood Indigo
Broadbent Gallery, September 27, 2007, to August 31, 2008
Dr. Anne Bissonnette, Curator