St. John’s Indigo Years

(This article first appeared in the summer/fall 2004 edition of the Kapok Chronicles, the official [bi-yearly] newspaper of Virgin Islands National Park. Don Near, editor of the publication, is an Interpretive Ranger and has been with the Park for 21 years. We thank Don for allowing us to reprint his informative article.)

The word indigo may conjure up a state of mind as in Duke Ellington’s blues song “Mood Indigo,” an “aura color” in New Age spirituality, or even a source of traditional folk medicine in the treatment of everything from fevers and headaches to convulsions and boils. But most people would probably equate the word indigo with a blue dye, reportedly the only natural source for blue and said to be the oldest dye of mankind. Today it is most commonly seen, in varying shades, in an estimated 2 billion pairs of blue jeans and other blue denim fabric world-wide.

Image: Indigo Works

While used for one reason or another in ancient cultures for thousands of years, the dye became commercially valuable in the Western hemisphere at the same time that the Caribbean islands were being colonized by Europeans in the 17th and 18th centuries. While short-lived, indigo production, along with tobacco, cocoa, coffee and ginger, dominated the plantation economies from Barbados to Hispaniola a hundred years before sugar and cotton would become the most lucrative crops in the region in the mid 1700s. On St. John, the time period was even shorter as the island was not formally settled by the Danes until 1718. At the Danish West India Company’s plantation in Coral Bay, indigo plants and the infrastructure for processing it were started in 1722.

Where exactly does indigo dye come from? There are hundreds of plants that will eventually produce this particular blue color (and all its gradations), distinct from purples, violets and other shades of blue. In medieval England and northern Europe the woad plant and Dyer’s Knotweed were lucrative sources of the dye. In warmer climes including Italy, India and Eastern regions, Indigofera tinctoria was the primary species used while in pre-Columbian Central and South Americas and the Caribbean it was I. suffructicosa. Woad yielded an inferior color, so that when the Caribbean was being colonized, the shift to the better Indigofera species took place in those locales. Often the tinctoria species was imported to replace the lesser-valued native suffructicosa.

What may surprise you, however, is that whatever the dye source might have been, be it for fabrics, African or Mayan face painting, tattoos, or other uses, there is actually no blue color in any of these indigo-bearing plants. The green leaves (and sometimes stems) of “indigo” plants yield a yellow or greenish color that turns blue with the magic of oxidation, especially as induced by man.

Although the growing and harvesting of the plants was not particularly hard work, the processing was neither a pleasant nor healthy enterprise. On St. John and in other tropical areas bundles of un-bruised leaves were submerged in a large vat of clear warm water for several hours to a few days until the water“boiled” in the rapid fermentation of the plant material. This vat’s water was drained off and the rotting, stinking mash of fermented leaves was transferred to a second vat of water whereupon it was beaten by paddles or whisked with sticks or by hand in order to bring oxygen to the mix. In this stage the resulting vapors given off by the foul water were particularly nauseous and noxious. Repeated long-term exposure is now known to be extremely caustic to the respiratory system and can cause cancer.

The oxidation begins the precipitation of color from the mash that settles to the bottom as a deep blue sludge. Another draining followed by soaking in a third vat leads eventually to a final draining, as more of the blue pigment sinks to the bottom. T he sludge was then filtered through thick woolen or coarse canvas bags to remove impurities. The pulpy mass is compressed to remove as much moisture as possible before it is shaped into blocks (“cakes”) or balls of pure indigo dye. Dried in the air, they become hard and shiny.

But the fun doesn’t stop there. This newly created indigo is not water soluble and must be put through even more hoops to become utilized as a dye. The hardened indigo units are immersed in water in which several possible fermenting agents are added to yield an indestructible blue color. Fermentation by adding such things as bran, herbs, iron compounds potash, lime soda and an old-time favorite, aged human urine, turns the solution to the color of untarnished copper. To dye a fabric blue, oxidation again comes into play. It is dipped in for a few minutes and when raised out of the solution and into the air, the cloth turns from yellow to blue. The concentration of the indigo doesn’t determine the intensity of the blue. A darker shade of blue can only be achieved by repeated immersions for the same cloth.

It is arguable as to whether the replacement of indigo production in the Caribbean by more profitable sugar and cotton was any healthier for the enslaved people doing all the work. The fumes and cancer might have been gone, but the latter crops were far more back-breaking and intensive overall. Local historian David Knight theorizes that the scarcity of water may have been a further consideration for the profitability of indigo growing on St. John-not for the growing of the plant, but for the large amounts of water needed in the fermentation/precipitation process. In any event, by the 1900s the bulk of commercial indigo was produced synthetically by using chemicals instead of plants. Developed by the German company BASF, the artificial process was quicker, easier, healthier for human producers and yielded a dye more uniform in concentration than natural indigo.

These days, natural indigo use is mostly limited to artists, craftsmen, textile conservationists and historians, or for traditional medicines. There is nonetheless increased interest in returning to the old ways. Cottage industries for the natural dye still persist in Central America and Mexico (the smaller quantities involved are less toxic to workers) and a fast growing segment of the fashion industry is one that purports the use of natural fibers using natural dyes. Indigo can even be obtained nowadays in powdered form which, according to a recent edition of the New Agriculturist magazine, not only speeds up the dying process by eliminating the extraction phase for solubility, but greatly decreases the hazardous solid and liquid wastes involved in the dye fermentation/precipitation vats, which saves human health and the environment.

In the future, the increasing markets for natural indigo could include use in Inkjet printers, which currently use environment-unfriendly ink that unless recycled ends up in landfills. The European Union, which aims to satisfy 5% of the galloping European (and world) indigo market with natural sources by 2005, could incite a whole new wave of indigo plant growing in the Caribbean and other tropical areas. Perhaps in a few years an indigo species will once again prevail on St. John as a legitimate agricultural crop rather than as a common roadside weed that it is here today.


Don Near

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