The following is way more than you wanted to know about indigo but if you are a serious dyer, there will be valuable information.
There are many methods of dyeing with indigo. Basically, two things have to happen. First, the bath must be made alkaline so that the indigo will dissolve. Urine, ammonia, baking soda, lye, are all used for this purpose. Second, the molecular structure of the indigo must be changed in order for the dye to penetrate and adhere to the fiber. Here are several methods.
Stock Solution Powdered Indigo – 6 Tbls. Lye (sodium hydroxide) 3 1/3 Tbls Thiox (thiourea dioxide) 2/5 tsp
Mix indigo with enough water to make a lump free paste. In a separate container, add Lye to 3 cups water, carefully. Lye is caustic. Never add water to Lye. Set aside to cool. In another container, add Thiox to 1/2 cup water. Stir gently to dissolve.
Slowly add the lye solution to the pasted indigo, stirring to make as smooth a mixture as possible. Add Thiox solution slowly to avoid making air bubbles. Stir gently from time to time until reduction is complete. (turns yellow) Raise temperature no higher than 135 degrees for 15 to 30 minutes.
Warm water (120) 6 gallons unflavored gelatin powder 2 tsp Synthrapol 2 tsp Ammonia 4 Tbls Thiox 2 tsp.
Put warm water into dye pot. Mix in order listed making certain each item is thoroughly mixed before adding the next. Add reduced stock solution by carefully lowering the container into the Dye Vat and sliding the liquid out at an angle. Stir gently. After 30 to 60 minutes the vat should be clear greenish-yellow.
Add thoroughly wet-out wool. soak wool in dye vat for 30 minutes. Remove wool, Let wool oxidize for 15 minutes.
After final dip and fiber is fully oxidized, gently wash in warm bath of Ivory flakes or soap and rinse until water is clear. Soak for 10 minutes in room temperature water to which 2 Tbls vinegar per gallon has been added.
Safety - wear rubber gloves. Lye can cause severe burns.
First aid – eyes and skin- flush with cool water for 20 minutes. Get medical attention. If swallowed – rinse mouth with cold water, drink one or two glasses of milk or water. Do not induce vomiting. Get medical attention.
1. If vat appears grayish and watery, it is exhausted. Add more stock solution. 2. If vat has been left for a few days, it may need a small amt of Thiox – 1/2 tsp., dissolved in water. 3. If the vat changes from yellow-green to blue, more Thiox is needed. Add small amount – 1/2 tsp for full vat, dissolved in water. Wait 15 minutes and check vat again before dyeing. 4. If white specks appear or vat appears milky, add 1 tsp lye in 1/2 cup water. 5. Always dissolve Thiox and Lye in water before adding to dye vat. Do not add dry flakes. 6. Cover with saran wrap when not in use.
Plant to Dyestuff
1. Indigo plant cut as mature.
2. Plant steeped and allowed to ferment
3. Solution containing indigotin drawn off.
4. Solution beaten with paddles to promote oxidation.
5. Solution allowed to settle and water drawn off.
6. Indigotin is pressed, cut, and dried.
Indigo cakes or “junks” can now be stored until ready to use. It is said that the early American settlers stored their lumps of Indigo under the floor boards in the attic. There was at that time no substitute for blue amongst the herbs in the garden. Often the fermentation vat or “blue pot” was kept ready to use for months by replenishing ingredients as needed.
DYEING WITH FRESH JAPANESE INDIGO
Different as they are in other ways, indigo, Japanese indigo, and woad all produce the blue pigment called indigo. In every case, the traditional methods for using the indigo from these plants have involved processing large quantities of the leaves to extract and concentrate the pigment into solid lumps of blue stuff which could be stored indefinitely. For dyeing, the blue lumps had to be ground into a fine powder, dissolved in a vat of stale urine, and fermented for several weeks. All in all, it was a tricky, slow, and smelly process.
This modern method of using indigo is easy, fast, and virtually odorless. It’s a practical way to use the leaves from a small patch or row of plants and to dye enough yarn for a hat, a scarf, or pair of mittens. I start with the fresh leaves, extract the dye, and use it right away. From start to finish, the process takes only about four hours. Dyeing with fresh indigo is just as easy as using other dye plants, but the process is quite different. You don’t boil the leaves or simmer the dyebath, and you don’t have to mordant the yarn. You do need one special ingredient called a reducing agent. My favorite reducing agent is Thiox, an inexpensive white powder sold in small packets by dye suppliers. For this recipe, use 8 ounces of indigo or Japanese indigo leaves. This will be enough to dye 2 to 4 ounces of fiber, depending on what fiber you dye and how dark a blue you want.
1. Pick fresh leaves and immediately put them into a clean, heat-resistant container. This doesn’t have to be a metal dyepot – it can be a large glass jar or a heavy-duty plastic tub or pail You don’t have to shred or grind the leaves; just put them in whole.
2. When using indigo or Japanese indigo leaves, add just enough hot tap water to cover the leaves, cover the container, set it into a larger pan of water(like using a double boiler), and put the two containers on the stove. Over low heat and using a thermometer to monitor the temperature, heat the water in the pot to 160°F over a period of about two hours.
3. Strain off the dark, warm fluid into another pot. Wearing rubber gloves, squeeze the fluid out of the leaves and add it to the strained fluid. Discard indigo leaves now.
4. The dark fluid contains a precursor of indigo called indoxyl. Add one tablespoon of baking soda or ammonia to the fluid to make it alkaline, then pour the fluid back and forth from one container to another. As the indoxyl reacts with oxygen in the air, it will change into indigo, and the solution will turn to a dark blue-green or blue-brown. Keep pouring it back and forth for a few minutes.
5. The indigo isn’t ready to use at this point. To prepare it for dyeing, it must be converted from the blue form into a yellowish form. That’s what the reducing agent does. Dissolve 1 tablespoon of fresh
Thiox in a jar of warm water. Pour it into the dark dyebath and stir briefly. Cover the container and set it in a larger container of water ,just hot enough to keep the dyebath at a temperature of 100° to 120°F. If it is over 120, let it cool first. Don’t overheat it.
6. Meanwhile, put the yarn in hot water to soak. While the yarn does not have to be mordanted, it must be good and clean. You may dye the yarn all at once or divide it into two or more batches and dye them separately to get different shades of blue.
7. After an hour of so, when the dyebath has turned yellow, add the wet yarn, carefully lowering it down below the surface. Leave it to soak for 20 minutes or more, then gently lift it out of the dyebath. Like a miracle, the yarn will turn from yellow to blue as it reacts with oxygen in the air. Let the yarn dry in the air for as long as it soaked in the bath. One dipping and airing is usually enough to give rich colors on wool yarn, but to intensify the colors on cotton or silk yarn, repeat the soaking and airing two or more times. After the final airing, wash and rinse the yarn in a mild vinegar solution to return the pH to normal.
8. You can put two, three, or more successive batches of yarn into the same indigo dyebath, getting lighter colors each time, until the pigment is all used up and the yarn no longer turns blue. Then discard the dyebath (it’s safe to pour it down the drain) and scrub any stains out of the pot.
Things can go wrong. If you don’t get a good blue, here are some possible explanations:
* You picked leaves too early or too late in the season.
* You let the picked leaves sit around before heating them in water.
* You didn’t heat the water enough, or you heated it too fast, or the water overheated.
* You forgot to add the baking soda or ammonia, or you added too much.
* The Thiox was stale, and/or you didn’t use enough.
* You tried to dye too much yarn for the amount of leaves that you had.
* You abandoned the dyebath for a day or longer. If not used promptly, it can go bad.
Short Fresh Indigo Recipe
1. Pick 16 oz indigo – put in plastic bucket – cover with hot tap water.
2. heat to 160 degrees over a period of two hours.
3. Strain off liquid. Squeeze indigo
4. (indoxyl) Add two tbls of baking soda – stir a bit.
5. Pour back and forth to oxidize the indoxyl and change it to indigo – until it turns dark green/blue.
6. Dissolve 2 tbls thiox (thiorea dioxide) in warm water. Pour into dyebath. Cover and set in water.
7. Wait one hour until bath is yellow at around 100 – 120.
8. Add hot wet yarn – leave for 20 minutes. Take out and let oxidize.
9. put in Vinegar rinse.
1. Make stock solution – mason jar – 110 – 140 degree water.
Dissolve 3 tbls lye. Add 5 tbls synthetic indigo (this seems like a lot. I usually put in less) and stir 2 min.
Add 2/5 tsp thiox – stir 1 min. Set aside 15 0 60 minutes til reduced. I usually let it sit all night.
Will keep for a while. if it oxidizes – heat and add more thiox.
2. Fill 5 gal vat with hot tap water – 110 to 140 degrees
3. Add 3 1/2 tbls ammonia
4. Add 2 tsp gelatin and 2 tsp synthrapol
5. Add 2 tsp thiox – stir – let sit a bit
6. Add the stock solution allow to reduce – takes 10 miuutes to an hour or so.
7. 10 minutes first dip. – Dip over and over if you want dark color. Allow to oxidize
8. Vinegar rinse to neutralize
1. pee in bucket – let sit a week or so – need 4 gallons
2. put natural powdered indigo – 1 oz – in cloth bag. put in urine.
3. Every day for as long as it takes (a month) rub the bag and put back – be careful not to oxidize the vat.
4. Lower wool – let sit up to 24 hours. Oxidize.
5. Wash in soap until smell goes away
The Dye Process
The dye process for indigo differs from other dyes due to the inherent properties of the dyestuff; It requires a chemical reaction in order for it to adhere to the material and it is not soluble in water.
The three necessary components in indigo dying are:
1. Conversion of indigotin to leuco compound called indigo white. The indigo releases its oxygen to bond with the free hydrogen released by the reducing agent. This process is known as reduction of the indigo.
2. Addition of an alkaline substance permits the indigo to become soluble in water.
3. After removal from dye vat the indigo white adhering to the material returns to its original chemical state of indigotin by removing needed oxygen from the air. The material actually turns from yellow to blue before your eyes. This process is known as Oxidation of the indigo.
Reduction – Bacteria needs oxygen for respiration. It first pulls free oxygen from bath. When that is used up, then the Bacteria takes the oxygen from the water molecules, liberating hydrogen, which converts the Indigo Blue (O=C-C=C-C=O) to Indigo White (HO-C=C-C=OH). It is then soluble in alkali.
Indigo is derived from a shrubby legume growing to be five feet tall. It grows in many parts of the world and was commercially cultivated in the southern United States. Eliza Lucas Pickney brought the plant to South Carolina from England in 1747 and it was a staple crop from the 1740’s until the revolution.
Natural indigo was chemically synthesized in the 1870’s but until then was the major source of blue dye the world over. Since that time its commercial use has declined. Many hand dyers, however, realize that indigo blue is a beautiful, intense, fast color, that is almost miraculous to attain.
The blue dye derived from the indigo plant is called indigotin. It requires 100 plants to provide four ounces of indigo and six and a half pounds of indigo to dye 100 pounds of cloth.
Although indigo may appear difficult to work with due to the many methods used to attain the blue color and the fairly complicated procedure, once you understand what happens, it becomes surprisingly simple.
madder quick lime
yeast pearl ash
sugar soda ash
molasses wood ash
ferrous sulfate quick lime
sodium hydrosulfite washing soda
thiourea dioxide (Thiox) sodium hydroxide (lye)