One of the oldest dyestuffs and one with a fascinating history, indigo has always carried in its shade and its name an exotic, mysterious, and at the same time luxurious connotation in people’s mind. It is believed that India was the first country to master indigo cultivation and processing. In the Middle Ages, indigo was an expensive scarcity imported to Europe from India. Similar to the case of silk, indigo traveled from East to West through a trade route ran by merchants in the Mediterranean. The price of indigo went down and its popularity bloomed after the 15th century thanks to two main factors, one being the Portuguese voyagers opening a direct sea route between West Europe and India; the other factor being the rush to cultivate indigo in various colonial plantations in the Americas. From North Carolina to the colonized islands in the Caribbean, indigo became one of the most prominent cash crops. Benjamin Franklin reportedly brought with him 35 barrels of indigo in his voyage to France in November 1776, offering one of colonial’s most valuable export commodity in exchange for help in the American Revolution. For thousands of years, different civilizations have learned to tame this mesmerizing yet hard-to-deal-with dyestuff, successfully extracting the blue pigment (indican) from around 150 varieties of plants. Each continent has its own prominent variety, yet not all indigo are equal. Before European settlers introduced “true indigo” (indigofera tinctoria) from Asia to the Americas, the people there had been cultivating their indigenous añil (indigofera suffituosa). Anil is present in the renowned “Maya blue” – a color closer to turquoise than indigo.
Europe has its own natural blue obtained from woad (isatis tintoria), cultivated in highest density South of France and North Italy. At one point in history, woad became one of the three major dyestuffs in Europe, alongside with weld (yellow) and madder (red). In the Languedoc region in the South of France, the evidence of a once hugely successful business remains today in the opulent mansions of woad merchants. France and Germany once banned imported indigo with the hope of saving the (tax money from) domestic woad business. However, the French colony Saint Domingue (Haiti today) started producing indigo in a quantity so large and quality so good that they supplied to several countries in Europe, mostly through smuggling, that France loosened up on their risk-averse mindset.
Indigofera tinctoria – a species native to the warm regions of Asia – has been regarded as having the highest quality. The concentration of indican – the bitter, water soluble, natural blue pigment – can be 30% higher in indigofera tinctoria than in woad. When processed well, indigofera tinctoria yields pigments that can give fabric a dark, deep blue with a tint of purple gloss. This explains its “true indigo” name as well as the frenzy over indigo from the East, namely India, in the Western world.
While India is believed to be the birthplace of indigo, when or how the knowledge of indigo cultivation and processing techniques spread to East Asia is unknown. China had historically used the indigenous Chinese indigo (polygonum tinctorium) for dyeing and printing before indigofera tinctoria spread from the south. Well-known for its indigo jukata and noren, Japan only saw a rise in indigo during the Edo period when the ban on silk gave rise to cotton, the latter so difficult to dye that indigo rose to become the prominent dyestuff. Because of its cold weather, Japan also hosts the polygonum tinctorium. As you move further south, the climate allow for more prosperous indigofera tinctoria to grow.
In Vietnam, indigofera tinctoria is omnipresent in highland and mountainous areas. Many different ethnic minorities have been using this plant, which is called “cham” by the locals, to dye their cloth. Vintage textiles of various ethnic groups carry indigo but the color varies from a blueish green to pastel and deep blue. The H’mong group is known to possess the highest level of knowledge and skills passed down through generations in terms of how to process “cham” to give the best blue quality. The deep, glossy blackish blue with a violet tint of their indigo cloths corresponds with the description of best quality indigo that has been historically imported to Europe.
Other ethnic minorities known for their indigo dyeing include the Dao, Lo Lo, Tay, Nung and Thai. When put next to each other, it is easy to recognize the subtle difference in the shade, tint and hue of different groups’ indigo. Even swatches dyed by the same person at different time of the year bear different color value. The Indigo chip in my Pantone book did not match any indigo fabric swatch I got. This thousand-year-old dyestuff never ceased to fascinate and surprise.