The plant Indigofera Tinctoria grows in abundance in Southeast Asia and the Indian subcontinent, it is a different species from Persicaria Tinctoria or Japanese and Chinese Indigo which grows in East Asia and Eastern Europe. For millennia the indigo plant has been used to create the most brilliant natural blue dye that was traded, like money. It can be said that dye even predates our modern currency whether as indigo dye bricks or as indigo fabric lengths. In Thailand, in the province of Sakon Nakhon in the Isan region or Northeast of the country, Indigofera Tinctoria grows in abundance with Sakon Nakhon Indigo protected as a Geographical Indication.
The leaves and stalks of the Indigofera Tinctoria plant goes through a process that transforms it from a plant to a living, breathing natural blue dye.
FROM PLANT TO DYE
For the leaves of the indigo plant to become a dye, a method that has been passed on for generations is used. The leaves are soaked overnight in water with red lime (clay), the alkaline in the lime bringing out the indigo colour in the water. After 24 hours, the surface of the water will reveal a copper colour, the leaves are removed and thereafter the indigo is "beaten", imagine beating Matcha, the colour is beaten out of the liquid, revealing a blue colour. The blue liquid is then left for another 24 hours to settle, thereafter it is strained through a muslin cloth leaving a thick indigo paste. For the paste to become a dye, it then goes through a fermentation process where water, clay, alcohol and fruits are added to it to create a liquid dye, thriving on the right balance of acid and alkalinity.
Indigo is a natural breathing dye, it needs a balance of acid and alkalinity with an ideal pH level of 10.5 - 11.5 and temperature of between 68-90°F (20-32°C) . It needs to be fed for it to ferment, we use tamarind (the juice squeezed out from the fruit), red lime and rum for our vat here in Bangkok, for our Bushwick vat, we use apple cider (from the store), pickling lime and vodka (leftover from a dinner party). After the vat is used, it needs to to rest and soak up the nutrients, to ferment and be fresh the next day. A healthy vat has a layer of blue foam on top that is shimmery and beautiful.
Natural indigo binds to natural fibres (does not penetrate it but creates a coat). To dye indigo, first soak the fabric to open up the fibre, wring out water. Dip into indigo vat and gently massage indigo into it. Wring out excess indigo in the vat. When the fabric comes out of the vat, it will be green, the moment that it breathes air it will oxidise and turn blue. Let hang dry for a few minutes. For a darker shade, repeat this process before washing. The indigo-dyed fabric must go through a few washes till the water runs clear.
NATURAL PROPERTIES OF INDIGO
Natural indigo is anti-bacterial and anti-microbial, the way that it binds and reacts to the fabric creates a shield which is also able to block out bacteria and microbes naturally. It also has natural UV-protection. Additionally, many think that indigo is cooling, this might be because the UV protection as well as the colour being cooling and calming.
Pink-flowered true indigo plant, Indigofera Tinctoria. Handcoloured copperplate engraving of a botanical illustration by J. Schaly from G. T. Wilhelm's "Unterhaltungen aus der Naturschischte" (Encyclopedia of Natural History). Vienna, 1817.
The red earth of Baan Don Goy in Sakon Nakhon turns into a vermillion orange mud when mixed with water. This rich mixture of earth and water is abundant with minerals and natural pigment. This pigment becomes natural dye that turns clothes into a color we call Dune.
MUD IS FILTERED THROUGH A MUSLIN CLOTH CREATING A SMOOTH DYE LIQUID. THE DYE IS MASSAGED IN THE GARMENT EVENLY AND THEN HUNG OUT IN THE SUN TO DRY. ONCE DRY, IT IS DIPPED AGAIN IN THE MUD DYE. THIS PROCESS IS REPEATED UNTIL THE DESIRED SHADE OF ORANGE IS REACHED. THE GARMENT IS THEN TAKEN TO THE CREEK TO BE RINSED WITH THE NATURAL CURRENT HELPING WASH AWAY THE MUD.
Pradu is a colour we have been working with for some time since Khun Mae Sa-ard of Baan Dong Siew showed us the warm colour. Pradu (Pterocarpus macrocarpus) is a rosewood tree and the outer bark is sliced off to make an all natural plant dye but soaking the bark in water overnight. It is believed that to get the most vivid colour, it is best to go when the sun is high up in the sky and before you remove the bark it is important to ask the tree for permission and ask her to give you a beautiful colour.
Once sliced from the tree trunk, the bark will have a reddish brown colour. Fresh dirt is rubbed into the incision on the trunk to help regeneration. It is important not to take too much bark from a single tree as it must be given time to regrow. Each tree has a different hue, the younger ones brighter, the older ones deeper.