indigo

Gardening Blues: Growing Japanese Indigo

by Donna Druchunas
photos by Dominic Cotignola

Click here for information on growing Japanese Indigo

Namahazome - Raw Leaf Dyeing

Using fresh leaves to create an indigo dye bath has recently been rediscovered as a modern process; however, this is actually the oldest form of ingido dyeing. The use of the Japanese indigo, or tadeai , plant dates to the 7th century A.D. when it was used chiefly by the Japanese aristocracy. The earliest method of indigo dyeing in Japan was known as "namahazome," which means "raw leaf dyeing." In the more well-known process of vat dyeing ("tatezome"), the leaves are fermented to produce a processed indigo product.

This 12 liter (3 gallon) recipe, which uses chemicals that were not available to early dyers, will dye 100-200 grams (4-8 ounces) of yarn or fleece various shades of blue. The entire process takes between four and five hours, so make sure you set aside enough time to finish.

Ingredients:

Freshly picked Japanese indigo leaves
Tap water
15-30cc (1-2 T) baking soda or non-sudsing amonia
1 package of Rit® Color Remover (available at grocery and craft stores, check the expiration date)
100-200g (4-8 oz) of wool yarn or fleece

1. Brew an Indigo Tea .

As soon as you pick the fresh leaves, put them into glass jars and fill the jars with warm tap water. I generally make a dyebath using six two-liter (half-gallon) milk bottles, but a plastic bucket, or stainless steel or enamel pot will also work.
To create a double-boiler, place the jars in a large pot on a rack to make sure the glass does not touch the bottom of the pot.
Slowly bring the temperature to 70ºC (160ºF). Do not exceed 80ºC (180ºF.)
Let the leaves steep for an hour. The liquid in the jars will turn a bluish-brown color.

Figure 1: Indigo Tea

2. Adjust the pH.

Wearing rubber gloves, strain the liquid into an enamel pot and squeeze the excess fluid out of the leaves. Throw away the leaves.
When the dyebath has cooled down to 50ºC (120ºF), add 15cc (1 T) baking soda or non-sudsing amonia to the dye liquid to make the vat alkaline (pH 7.5-8).
Use a wisk to agitate the liquid and add as much air into the vat as possible. The liquid will turn blue and a bit foamy. If this does not happen, add 7cc (½ T) of baking soda and continue to wisk.

Figure 2: Frothing the Dye Bath

3. Create the indigo white dyebath.

If necessary, apply low heat to raise the temperature to 50ºC (120ºF).
To remove the oxygen from the dyebath, dissolve about 20cc (1½ T) of Rit Color Remover in a small cup of warm water. Gently stir this into the dyebath, being careful not to introduce any air.
Remove the pot from the heat, cover and let stand for 15-45 minutes, or until the liquid turns a yellow/chartreuse color.
While you are waiting, soak your scoured yarn or fleece in hot water. It should be thoroughly saturated.

4. Dye your fiber.

Squeeze any excess water out of the yarn or fleece and carefully lower it into the dyebath. Stir it around gently under the surface, cover the pot, and leave it to soak for about 20 minutes.

5. Watch it turn blue.

Gently lift the yarn or fleece out of the pot, making sure you dont splash or get any oxygen into the dyebath. Magically, before your eyes, it will turn to yellow to green to blue as it oxyidizes in the air.

Movie: Oxidizing the Fiber (Press > to Play)

For darker shades, repeat the process (oxidize for 20-30 minutes between dips) until the vat is exhausted. You may add more baking soda to maintain the pH, more Color Remover if you get air into the vat, or more heat to keep the temperature between 40 and 50ºC (100 and 120ºF).

When you achieve a shade of blue you like, rinse your yarn or fiber thoroughly and spread it out to dry out of direct sunlight.

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