Get blue at home: do it yourself indigo
BY Keith Recker | May 31, 2009
Natural dye master Michele Wipplinger shares her indigo recipe with HAND/EYE readers
Michele Wipplinger, founder of Seattle-based Earthues, is a natural dye expert extraordinaire. The endless range of subtle, sophisticated colors she produces with all natural plant and mineral combinations serves as her curriculum vitae. She can tell you where she first made each combination, what culture her recipe is most influenced by, what the color means in several different regions, the challenges of making a dependable color with the particular plant material required – and so on. Her artisan-specific trend forecasting, the memorable training protocol she uses when on the road in far away places, and her mastery of her craft, are each remarkable and unique.
Try her indigo recipe at home with a tie-dye project – or with a simple overdye on a pair of much loved blue jeans. We highly recommend that you purchase her natural indigo dye kit at www.earthues.com: it makes the process more dependable and ever so much simpler. If the dyeing turns out well, you might consider her other natural color kits and try for a range of purples, reds, and yellows, too!
THE Earthues INDIGO RECIPE
The Earthues NATURAL INDIGO KIT is an introduction to the art of dyeing blues. It is the magical, favored colored among many cultures. Indigo is a status symbol of the Tuareg of the Sahara and considered a precious color by the Dobag weavers of Turkey. The dyers of Rajasthan use indigo as their final creative step in intricate tie and dye patterning. Almost every blue jeans wearer should be familiar with indigo. It is the only dye in the world that starts blue, turns yellow, changes to green, and then finally transforms itself again to true blue.
The dye kit contains natural indigo, soda ash, thiourea dioxide, hide glue, and gloves and a mask. It will dye approximately 5 pounds of material or yarns in the deepest indigo shade.
PLEASE NOTE that you will also need a small amount of sodium hydroxide (lye) to dissolve the indigo. Due to shipping restrictions, you can procure it yourself from grocery and hardware stores or soap making supply companies. Look for household lye, sodium hydroxide, caustic soda. Its chemical formula is NaOH.
A Note about Dye Kettles
The types of dye kettle you use can alter a color or change the chemistry of the indigo dye vat itself. There are three main types of kettles readily available; here are the pros and cons of each type of kettle.
Aluminum: Aluminum pots are among the most reasonable priced of all kettles. However they dull colors during the dyeing process. They are not recommended for any plant dyeing because the colors will be light and lack vibrancy.
Enamel/Porcelain: Enameled or porcelain kettles, often called lobster pots or canners, are good dye vessels. They do not affect the color as long as they are not chipped, pitted or worn. A chipped surface will expose the metal under the enamel, which will rust and cause dull or uneven colors.
Stainless steel: Stainless steel kettles are the best quality dye vessels available. They will not alter the color of any natural dye bath and will virtually last forever. Choose heavy-walled stainless steel vessels 18/10 gauge. The thin, shiny variety can leach metal which will alter the color of your dyebath.
Background on indigo
The scientific name of the indigo plant we use is Indigofera tinctoria, and we use fermented (and then dried) leaves in our kit.
Indigo is the only natural blue dye used by many cultures in unrelated places on every continent. Its history is illustrious. Independence in India was fought for and won in part because of the commercialization of indigo. A famous jeans company, Levi Strauss, has based its entire business since 1873 on one color, indigo blue. Each culture, each village, each dyer, has a unique way of making the magic of indigo work. Indigo, more than any other natural dye process, is elusive. Stories unfold about why this vat was successful and another failed. With this in mind, the journey to learn the secrets of indigo blue is at times serendipitous.
Indigo cultivation is good for the soil and the farmer. At least two crops can be grown and harvested per year in combination with wheat, corn and other staples. The nitrogen that indigo releases back into the soil further promotes the growing of food crops. There are over 275 varieties of plants that have usable amounts of indigo in their leaves. Indigo is easy to grow and it has naturalized in diverse climates all over the world. Regardless of the plant used, there is only one method for converting the leaves into dye. The indigo color is slowly drawn out of the leaves by composting them in alkaline water. Over 12-18 hours the water turns blue; it is then drained from the leaves and reserved. The resultant blue water is vigorously beaten or paddled to add as much air as possible to the solution. After hours of this beating, the indigo dye settles to the bottom of the vessel. The water above the sediment is drained. The remaining blue sludge is dried and sold as chunks of indigo in the market.
Indigo is a vat dye that requires no mordanting. However, it does necessitate a specialized dye process. The dyebath must be alkaline and the water reduced of oxygen. Only under these two conditions will indigo dissolve and change color so it can be applied to any natural material.
Making the Extract Stock Solution in Preparation for Dyeing
1. Put 2 oz. of natural indigo into a quart glass jar with a wide mouth.
2. Add 1/4 cup warm water (80° F) and stir to make paste.
3. Add one more cup of water and stir. The solution should be opaque and blue.
4. Add two TBS of an alkali (e.g. sodium hydroxide or lye) to dissolve the indigo. Stir carefully. Always wear gloves, mask and protective eye-wear when measuring and using lye. Do not breathe the stock solution vapors after adding the lye to the jar.
5. Next dissolve two TBS thiourea dioxide into nearly boiling water (one cup), add to the stock solution and stir until dissolved. Wear a protective mask and avoid breathing the stock solution vapors. Add enough warm water to reach the neck of the quart jar and stir gently.
6. Allow this stock solution to sit for 15 minutes so it can dissolve and reduce. The solution will change from a dark blue to a translucent green-yellow with a coppery scum on the top. Check to see if the stock is ready by dribbling some solution on the side of a white plastic cup and note the change from a transparent green-yellow to a dark opaque blue once oxidized.
This stock can be kept indefinitely if stored in a dark cool place and sealed securely. Natural indigo extract always has a distinctive grassy odor because it is often composted with local organic matter prior to exporting. If the stock turns blue over time, add a scant 1 TBS of dissolved thiourea dioxide. Check the pH to see that the stock remains pH 11, if not add 2 tsp of lye and stir well. If some of the stock evaporates over time simply add warm water and 1 TBS of dissolved thiourea dioxide, stir well. Wait for 15 minutes until the stock once again reduces and changes color.
Dyeing with Indigo
1. Fill up the dye kettle with warm water; 120°-130 F for wool and silk, 90 - 100F for cotton or linen.
2. If you are dyeing protein fibers (silk or wool), follow this next step. In a separate container or jar, soak 3 TBS of hide glue in lukewarm water until the grains swell, about 20 minutes. Add about two cups of very hot water and stir until dissolved. You will add this hide glue solution once your vat is sharpened.
3. Add the one half cup of dye stock, stir well and note the color of the dyebath. If after 15 minutes it remains an opaque blue color it needs to be sharpened.
4. Check the pH of the dyebath with your pH sticks.
• Wool and silk should have (and can have if using hide glue) a pH 10-11. Cotton and cellulose fibers have a pH of 11.
• If the pH is low, increase it by dissolving ½ cup soda ash in 1 quart of hot water. When it is dissolved, add all of it to the vat and re-check the pH of the dyebath.
5. Next add a little thiourea dioxide that has been dissolved in very hot water. Use 1 teaspoon of thiourea dissolved in 1 quart of very hot water. Add it about ½ cup at a time and wait for 15 minutes for the water to change color, or reduce. If the indigo water does not change, add another ½ cup of the thiourea solution and wait for it to reduce.
6. Once the oxygen is reduced, the indigo water changes color from blue to a green-yellow. Carefully note the color because it is an important chemical change that indicates vat readiness. The following color reference below will help guide your assessment of readiness for dyeing.
Opaque blue: The indigo bath is not ready for dyeing because of the oxygen in the water.
Clear blue-green: There is just a little too much oxygen in the dyebath. It is getting closer to being ready.
Clear greenish-yellow: The indigo bath is perfect; there is no oxygen left.
Clear yellow: There is an excess of the reducing agent (thiourea dioxide). Do not dye yet! Paddle the bath to reintroduce some air until it turns greenish-yellow.
7. The dye bath should be a clear green-yellow (not clear yellow!) with the appropriate pH and temperature for each fiber type before dyeing. If the dye bath is too yellow it is over reduced and dark indigo will be impossible to attain. As well, the excess thiourea will smell quite strongly of sulfur. If this occurs just paddle the dye bath to add oxygen until the color of the dye bath is correct. Once this has occurred dyeing should commence.
8. Add the dissolved hide glue solution to the vat and stir well.
9. Add the clean wet cloth, warps or skeined yarn to the dye bath. Keep the goods submerged the entire time and gently move them around under the water the entire dye period. Hold the goods in the dye bath from a few seconds to three minutes (maximum of five minutes) depending on the depth of shade required, the amount being dyed and the number of previous indigo dips. Basically the first dips should only be for 30 seconds to one minute. All subsequent dips can be from one to five minutes. Keep track of the number of dips.
10. Remove the cloth or yarn gently from the dye bath trying not to drip into the dyebath. Do not squeeze or wring your yarn or cloth. Allow the goods to oxidize (flat) in the shade for 20-30 minutes. Gently open up strands of yarn in the skein to allow oxygen to reach the inside of the fibers. After oxidizing dip again, repeating this sequence until the desired shade of blue is achieved. Keep in mind that at least two values of color will be lost to rinsing and drying. Therefore always dye two to three values deeper than required.
11. When do you add fresh indigo stock? Often you will need to add ½ to 1 cup stock if you notice that your dips are not getting any darker.
12. Where possible, oxidize 24 hours after the last dip and before washing.
The finishing process includes two steps: neutralizing and washing.
1. Neutralize all yarns after indigo dyeing by rinsing in either tannic acid (5 tea bags per pound) for cotton or acetic acid (1/4-cup vinegar per pound) for wool and silk. Soak (110° F) for 15 minutes until the rinse water is between pH 6 - 7.
2. Wash the indigo dyed goods in very hot water (170° F) with a neutral soap (Orvus paste or shampoo) for 20 minutes. Often it requires two to three hot water washings with fresh water to remove the excess indigo. End the process with a series of warm water rinses (no soap) until the color runs clear and the goods do not crock (rub off).
3. Because hide glue has been used to protect the cloth or yarn, they should be soft and supple after the indigo dyeing. Silk should have retained its sheen and strength and wool will be more lustrous than before the dyeing, and it too should be full and lofty.
Remember that the process of extracting and dyeing with indigo is an art. It is necessary to continuously experiment and make changes until you arrive at your own effective system.
For more information or to learn more about our specialty indigo, contact Earthues at www.earthues.com, or at firstname.lastname@example.org, or by phone at 206-789-1065.
Recipe by Michele Wipplinger and Earthues, www.earthues.com.
Earthues 1999, 2009 All Rights Reserved.
No parts of this text may be copied or reproduced without the express written permission of Earthues or Michele Wipplinger.