Though the process of turning green leaves into brilliant blue dye through fermentation has been practiced for thousands of years, it still feels magical. Most natural dye colors are derived from bark, berries, or leaves that can be boiled down and dyed with—but the process of making blue dye is much more difficult.
Every community—places like Mexico, Nigeria, and Japan—has its own spiritual rituals, recipes, and techniques for creating natural indigo dye. In India, the birthplace of indigo, dye paste is dried into cakes for easy transportation and trade. The synthetic dyes which enable today’s plentiful supply of commercial denim and tie-dyed products replicate the look of natural dye almost exactly. Since Levi Strauss created his first pair of workwear blue jeans with indigo in 1873, though, the process has changed remarkably.
As a freelance fashion designer, I’ve designed denim apparel for brands who have the manufacturing capabilities of washing, distressing, and styling denim for mass market. But when I first witnessed the wondrous natural process of making indigo from plant to paste at a small studio in Thailand, I fell in love with the traditional process and the brilliant color it produces.
This is the real deal. I have returned again and again to Studio Naenna in Chiang Mai to learn from esteemed author and artist Patricia Cheesman who has been practicing this art form for 25 years.
The Natural Indigo Dye Process
Here’s the 10 step process of making natural indigo dye as learned from Patricia and the team at Studio Naenna.
Step 1: Harvesting the indigo
The indigiferna tinctoria was planted during Thailand’s rainy season in June. By September or October, the plants are ready to be pruned and used for making dye.
Step 2: Bundling
We bundle the small leaf Indiofera tinctoria leaves together using stems as ties. The larger leaf varieties of indigo like Strobilanthes flaccidifolius can go straight into the bins.
Step 3: Soaking
Water is added to the bins. Heavy stones are used to press the color from the leaves during an overnight soak. The covered bins need to sit for about 24 hours, depending on the weather.
Step 3 (After 24 Hours…)
Voilà! Like magic, the water has fermented overnight and turned blue.
Step 4: Removing the bundles
The bundles are drained and removed. The plants are used for fertilizer.
Step 5: Adding lime
2% builders lime Ca(OH)2 is gently mixed into the colored water.
Step 6: The Beating Process (Part One)
The water and lime must be beaten for about 20 minutes – dipping the bowl in and out – oxidizing the mixture. The water changes from murky green to peacock blue to a frothy navy color.
Step 6: The Beating Process (Part Two)
When the mixture turns frothy and navy-colored it is almost ready. Patricia has an ear for the “sshhwaa” sound of bubbles breaking that is the signal to stop beating.
Step 7: Collecting the paste (Part One)
Patricia prepares the cloth for paste collection.
Step 7: Collecting the paste (Part Two)
After the indigo paste precipitated to the bottom of the bin overnight, we carefully removed the brown water from the top. The paste is then collected by pouring it over mesh (collecting debris) then though a fine cotton cloth.
Step 7: Collecting the paste (Part Three)
This is natural indigo paste, which can be stored in plastic bins for one to two years and used for dyeing later. Notice the beautiful variations in color.
Step 8: Preparing the vat
Dyeing takes place in the green form of indigo which is known, confusingly, as white indigo. The paste is mixed with ash water, fruit sugars or rice whiskey, and left to ferment. After a few days of stirring and adding sugars, it’s ready to dye with. Keeping an indigo vat alive is tricky, but Patricia has continually nurtured this vat for 25 years.
Step 9: Tie Dye and Shibori
Tie dye and Japanese Shibori are created by tying, rolling, stitching, and folding white cloth before dyeing. The tied-up portions of cloth remain white while the exposed areas turn blue in the indigo vat.
Step 10: Dyeing (Part One)
Cloth coming out of the white indigo vat has a green appearance but quickly turns blue with oxidation. Creating a light or a dark blue cloth requires multiple dips as indigo platelets are layered onto the cloth or yarn.
Step 10: Dyeing (Part Two)
Different shades of indigo after one or multiple dips in the vat.
The Finished Product
Mindy the Indigo Dog models a tie dyed handkerchief!