I find it funny those questioning the name of India , when one of the most ancient dyes is named after the "Indian Dye" that is Indigo or Neel in Sanskrit .
Before the Arabs called us Hind , the Greeks and Romans had been trading textiles and called us India .
Till almost 1880's there was no synthetic alternative to Indigo dye , till the Germans found one .
Synthetic dyeing is just about a 100 year old history . The whole world wore textiles only out of natural dyes till late 19th century .
Indigo is among the oldest dyes to be used for textile dyeing and printing. Many Asian countries, such as India, China, Japan, and Southeast Asian nations have used indigo as a dye (particularly silk dye) for centuries. The dye was also known to ancient civilizations in Mesopotamia, Egypt, Britain, Mesoamerica, Peru, Iran, and Africa.
India is believed to be the oldest center of indigo dyeing in the Old World. It was a primary supplier of indigo to Europe as early as the Greco-Roman era. The association of India with indigo is reflected in the Greek word for the dye, indikón (ινδικόν, Indian).
The color indigo was named after the indigo dye derived from the plant Indigofera tinctoria and related species.
The I. tinctoria species was domesticated in India. Indigo, used as a dye, made its way to the Greeks and the Romans, where it was valued as a luxury product.
Species of Indigofera were cultivated in India, East Asia and Egypt in antiquity. Pliny mentions India as the source of the dye, imported in small quantities via the Silk Road.
The Greek term for the dye was Ἰνδικὸν φάρμακον ("Indian dye"), which, adopted to Latin as indicum and via Portuguese gave rise to the modern word indigo.
The first known recorded use of indigo as a color name in English was in 1289.
Indigofera tinctoria, also called true indigo, is a species of plant from the bean family that was one of the original sources of indigo dye.
It has been naturalized to tropical and temperate Asia, as well as parts of Africa, but its native habitat is unknown since it has been in cultivation worldwide for many centuries.
Today most dye is synthetic, but natural dye from I. tinctoria is still available, marketed as natural coloring where it is known as neel in India , tarum in Indonesia and nila in Malaysia. In Iran and areas of former USSR known as basma. The plant is also widely grown as a soil-improving groundcover.
True indigo is a shrub one to two meters high. It may be an annual, biennial, or perennial, depending on the climate in which it is grown. It has light green pinnate leaves and sheafs of pink or violet flowers. The plant is a legume, so it is rotated into fields to improve the soil in the same way that other legume crops such as alfalfa and beans are.
Dye is obtained from the processing of the plant's leaves. They are soaked in water and fermented in order to convert the glycoside indican naturally present in the plant to the blue dye indigotin. The precipitate from the fermented leaf solution is mixed with a strong base such as lye.
Indigo remained a rare commodity in Europe throughout the Middle Ages. A chemically identical dye derived from the woad plant (Isatis tinctoria), was used instead. In the late 15th century, the Portuguese explorer Vasco da Gama discovered a sea route to India. This led to the establishment of direct trade with India, the Spice Islands, China, and Japan. Importers could now avoid the heavy duties imposed by Persian, Levantine, and Greek middlemen and the lengthy and dangerous land routes which had previously been used. Consequently, the importation and use of indigo in Europe rose significantly. Much European indigo from Asia arrived through ports in Portugal, the Netherlands, and England. Spain imported the dye from its colonies in South America. Many indigo plantations were established by European powers in tropical climates; it was a major crop in Jamaica and South Carolina, with much or all of the labor performed by enslaved Africans and African Americans. Indigo plantations also thrived in the Virgin Islands. However, France and Germany outlawed imported indigo in the 16th century to protect the local woad dye industry.
Indigo was the foundation of centuries-old textile traditions throughout West Africa. From the Tuareg nomads of the Sahara to Cameroon, clothes dyed with indigo signified wealth. Women dyed the cloth in most areas, with the Yoruba of Nigeria and the Mandinka of Mali particularly well known for their expertise. Among the Hausa male dyers, working at communal dye pits was the basis of the wealth of the ancient city of Kano, and they can still be seen plying their trade today at the same pits.
In Japan, indigo became especially important in the Edo period, when it was forbidden to use silk, so the Japanese began to import and plant cotton. It was difficult to dye the cotton fiber except with indigo. Even today indigo is very much appreciated as a color for the summer Kimono Yukata, as this traditional clothing recalls Nature and the blue sea.
Newton used "indigo" to describe one of the two new primary colors he added to the five he had originally named, in his revised account of the rainbow in Lectiones Opticae of 1675.
The demand for indigo in the 19th century is indicated by the fact that in 1897, 7,000 km2 (2,700 sq mi) were dedicated to the cultivation of indican-producing plants, mainly in India. By comparison, the country of Luxembourg is 2,586 km2 (998 sq mi).
In 1897, 19,000 tons of indigo were produced from plant sources. Largely due to advances in organic chemistry, production by natural sources dropped to 1,000 tons by 1914 and continued to contract. These advances can be traced to 1865 when the German chemist Adolf von Baeyer began working on the synthesis of indigo. He described his first synthesis of indigo in 1878 (from isatin) and a second synthesis in 1880 (from 2-nitrobenzaldehyde). (It was not until 1883 that Baeyer finally determined the structure of indigo.
17c. spelling change of indico (1550s), "blue powder obtained from certain plants and used as a dye," from Spanish indico, Portuguese endego, and Dutch (via Portuguese) indigo, all from Latin indicum "indigo," from Greek indikon "blue dye from India," literally "Indian (substance)," neuter of indikos "Indian," from India (see India).
Replaced Middle English ynde (late 13c., from Old French inde "indigo; blue, violet" (13c.), from Latin indicum). Earlier name in Mediterranean languages was annil, anil (see aniline). As "the color of indigo" from 1620s. As the name of the violet-blue color of the spectrum, 1704 (Newton).