How Much Indigo in the Vat?

As I learned to use organic indigo vats, I started with recipes from Michel Garcia: “one, two, three”. Michel talks about the vats in simple terms. It’s as easy as 1,2,3. This also represents the proportions of indigo, lime, and sugar that go into the vat:

  • 1 part indigo
  • 2 parts lime
  • 3 parts fructose sugar

It’s simple, right?

Not always.

I probably get more questions about making and maintaining an indigo vat than anything else. There are so many unknowns. It’s taken me a number of years to feel comfortable with those unknowns and to gain the confidence to solve problems with the vat.

I recently had several people ask me about the quantity of indigo in the vat. That’s an important question. Unless you know how much indigo, you can’t really determine how much sugar (or other reduction material) or how much lime.

I’ve watched Michel make vats with very small amounts of indigo and what I would consider very large amounts of indigo. What is the difference? Will you get a darker color from a vat with more indigo?

The answer is “yes” and “no”.

I made 3 small fructose vats with varying amounts of indigo

  • 2 grams indigo per liter of vat liquid volume
  • 5 grams indigo per liter of vat liquid volume
  • 8 grams indigo per liter of vat liquid volume

As you can see from the samples dyed the very next day, there was a great deal of difference in the colors produced from each vat. Even on day 3 there was significant difference. But one week later, the 3 shades of blue are much more similar. All of these samples represent only one 20-minute dip in the vat.

Dye tests done with a single long dip in the three different vats

Why would you use 8 grams of indigo per liter instead of 2 when you can get a similar color from both these options? There is more indigo in the vat, which means more can be dyed over a longer period of time before additional indigo must be added. If I were doing a short-term vat for a small amount of dyeing, 2 grams of indigo per liter would probably be plenty.

The questions to ask are:

  • What  quantity of textiles will  be dyed in the vat?
  • How many people will be using the vat?
  • How long do you want to keep the vat?
  • How quickly to you need to get strong color from the vat?

The coloration of the reduced liquid in the 3 vats is different, indicating varying amounts of indigo in reduction. But the textile is only able to absorb so much dye at a time. We always build up color with multiple, long dips in the vat.

Three indigo vats reduced with fructose: 8 grams, 5 grams, and 2 grams of indigo per liter

The other thing you can see through these glass jars is the amount of sediment at the bottom of the vat. The weakest vat has very little and it gets progressively deeper with the stronger vats. It’s important to keep our textile above this sediment when it’s dyeing.

I currently have a 30-liter vat that I have been using for over a year now. I’ve added indigo to it a couple of times, and of course plenty of reduction material and lime. The vat is still working well but over the months the sediment has gotten very deep, which has reduced my dyeing space so much that it’s time to make a new vat.

The “1,2,3.. ” proportions are guidelines and easy to measure if you’re using fructose. How many bananas or sweet potatoes do you need to reduce 10 grams of indigo? Take a good guess. Making small experimental vats in glass jars has taught me a great deal about how the vat works. We don’t always know but have to start somewhere.

Observe carefully. One must be patient with the indigo vat.

What We Call Things

While in Oaxaca, Mexico, a friend gave me a small bag of dried dye material. She had obtained it from dyers in the Teotitlan Valley. It was identified locally as “Mexican chamomile”. It was very aromatic and easy to believe that it was a type of chamomile, possibly related to dyer’s chamomile (Anthemis tinctoria), also known as know as golden marguerite.

I wanted to compare this “Mexican chamomile” with the chamomile I had at home. I had dried chamomile flowers from Maiwa and some whole plants from the end of the season in my garden. Both of them were Anthemis tinctoria.

Dry and fresh dye materials

I dyed mordanted wool fabric with all three of these “chamomiles” and achieved very different results. Both of the known chamomile dyes produced in a soft, predictable yellow color while the Mexican “chamomile” produced in a much deeper, richer tone. When I completed lightfast tests on the three samples, the Mexican chamomile actually deepened in hue, which led me to believe that it contained a tannin. I guessed that it might not actually be chamomile.

Fresh chamomile (Anthemis tinctoria), Maiwa dried chamomile flowers (Anthemis tinctoria), Mexican chamomile (Tagetes lucida)
Lightfastness tests. Right side was exposed to direct sun for 3+ weeks.

After reporting these results to the friend who had given me the dye, she told me the plant had another local name: “pericon”. Once I knew this, it was easy to identify the plant in both Tintes y tintoreros de América by Ana Roquero and Plantes Tintóreas de Guatemala by Olga Reiche. Both of these are excellent dye books, written in Spanish.

The dye plant in question was Tagetes lucida, a type of marigold. The entire plant is used for dyeing, which explains the presence of tannin in the dye. The whole plant is likely to contain tannins while the flowers alone would not.

Tagetes lucida,  Wikipedia photo

I have located sources of seed for this plant. The seed companies also refer to it as “Mexican tarragon”, “sweet smelling marigold”, and “Mexican mint marigold”. The leaves are a savory herb and can be used as a substitute for tarragon.

I bring all this up to emphasize the importance of using Latin names for our dye plants. Local names are only useful to local people. I understand that there is a great deal of emphasis on the use of local plants for dyeing but as we travel and meet dyers from other places it becomes important to talk about our process in a common, international language.

While in Mexico I took a workshop on plant taxonomy with Alejandro de Ávila at the Botanical Gardens in Oaxaca. I marvel at the incredible system of plant names that can be understood around the world and encourage dyers to get into the habit of using the Latin names for plants.

I will grow Tagetes lucida (or “Mexican chamomile”, or “pericon” or Mexican tarragon” or “sweet smelling marigold” or “Mexican mint marigold”) in my garden this year and think about the Teotitlan dyers who gather it wild and use in their weavings.

Jacobo and Maria Luisa Mendoza, Teotitlan weavers and natural dyers in their home studio, with Rocio Mena Gutierrez


Indigo Reduction Materials

Michel Garcia has inspired and informed many of us in the use the organic indigo vats. He has given us a simple one, two, three (1:2:3) recipe that refers the proportions of indigo, lime (calcium hydroxide) and reduction material (often a sugar).

But nothing is ever as simple as 1:2:3! Dyers work hard to determine how to keep their vat active, when to add reduction material, when to add  lime, and how to best dye their textiles.

A key issue dyers must think about is the selection of the best reduction material that is also readily available. Michel commonly recommends the use of fructose or a fruit that is high in sugar, such as bananas. These high-sugar materials assure that the indigo vat will go into reduction quickly and successfully. I recently had a reader ask me if dextrose will work as well as fructose. I didn’t know, so I tried it. It was slower to reduce, but in the end resulted in colors very close to those obtained with fructose. On the other hand, cane sugar resulted in no reduction whatsoever.

Vats were made with fructose and dextrose

In November I was in Oaxaca, Mexico for the 10th Intentional Shibori symposium, where Michel Garcia and I were both teaching workshops. Our time in Mexico proved to be another opportunity to realize how much more there is to learn about indigo vats.

One day, we were eating fresh oranges and Michel mentioned that we could use the orange rinds to reduce an indigo vat. I was surprised (and a bit skeptical) since I knew that oranges were acidic. It turns out that the orange juice is acidic but the rinds are full of pectin, which is an excellent reduction material.  We ate a lot of oranges, cooked the rinds, and used that juice to make our vat. Of course, it worked!

Further discussion of indigo vats in Michel’s class revealed that some vegetables can also be used to reduce the indigo vat: turnips, zucchini, etc. Some of these vegetables contain pectin as well as sugars.

I never really know something until I’ve tried it. In the last few weeks I have made nine small indigo vats using citrus skins and chopped vegetables. I made the vats in glass jars with 1 gram of indigo per liter of solution.  A great deal can be learned about an indigo vat when it’s made in a transparent container. I can see the color of the vat, the amount of un-reduced material at the bottom, and the speed (or slowness) at which the vats reduce. The use of the vat for dyeing is the ultimate test.

The “citrus series” was made with

  • Cooked orange rinds
  • Cooked lemon rinds
  • Commercially available ground orange peel
  • Commercially available pectin from the grocery story (additives included dextrose and fumaric acid)

When using fruit, I cooked the rinds from several small oranges or lemons in water and used that liquid as the basis of the vat. I used the 1:2:3 proportions (by weight) as a guideline for the commercially available orange peel and pectin (1 part indigo, 2 parts lime or calcium hydroxide, 3 parts reduction material).

Samples dyed in the vat 1 day after making the vat and 9 days later. Reduction of the indigo vat is sometimes not complete for several days. The vat made with cooked lemon rinds never reduced well and continued to have a great deal of un-reduced material in the vat. All dying is a single dip in the vat.

The “vegetable series” was made with

  • Zucchini
  • Turnip
  • Carrot
  • Sweet potato
  • White potato

I used the equivalent of one medium sized vegetable per liter of vat liquid. The vegetables were chopped into small pieces and boiled for 15-30 minutes or until the vegetable matter was very soft. The liquid was then strained to make the vat.

A vat in a pint size jar is enough for testing.
The color of the bubbles on the surface of the vats is an indication of the reduction. The light colored bubbles of the white potato vat (back row, center) indicates the weakest reduction. This is confirmed by the color of the vat and the dyed color on the cloth.

Every vat worked to some degree. In the “citrus series” both the orange rind vats reduced first, the pectin vat was slow but after a week the color achieved matched the orange rind vats. The lemon rind was the weakest from the beginning and also has a great deal of unreduced material at the bottom. The white potato was the slowest of the vegetables to reduce and the resulting color continued to be the weakest.

“Vegetable vats” after 24 hours and 5 days.

Some of these latest experiments were more successful than others but they were a huge revelation for me. There are indigo reduction materials everywhere! Some are better (and more available) than others. I can imagine a new use for the abundance of zucchini in the summer garden and I can use waste from my food kitchen to feed my indigo vat.

Several years ago I was doing indigo dyeing on the Island of St. John in the Virgin Islands. We harvested local Aloe Vera leaves as a reduction material. I later tried reducing a vat with Aloe Vera that was growing in a pot as a houseplant. The houseplant did not reduce the vat.

My studio doesn’t smell as sweet after cooking potatoes and turnips as when cooking orange rinds or bananas (neither does the vat), but it’s another valuable reminder of the complex world of natural dye and the resources at our fingers.

Growing Color: A Symposium and a Lifestyle

We are about to have our first killing frost here in western North Carolina and it’s time to collect seeds. This morning I watched a squirrel cross the road with an enormous black walnut in his mouth. There are plenty of black walnuts in the freezer. I’ve collected seeds from my French marigolds. I’m not sure of the tagetes variety but the seeds were brought back 8 years ago from Couleur Garance in Lauris, France and the plants grow taller (about 1 meter tall) than our garden shop variety. They produce plenty of flowers that are easy to harvest and dry.

My Japanese indigo (Polygonum tinctorium) is blooming so next year I’ll have my own seeds to plant. We had an unusually dry summer here and the seeds on the madder plants didn’t mature but usually I would be collecting those as well. I’ve been collecting and drying staghorn sumac (Rhus typhina) leaves as a great source of tannin.

The tiny weld (Reseda luteola) seedlings in the garden will turn into a valuable crop of dye next summer. Each year I harvest about 5 pounds of dried weld from a 4’ x 8’ bed.

As I prepare my own garden for the winter, the North Carolina Arboretum is preparing the first Growing Color Symposium, November 5,  2016. The event was conceived with the idea of dyers and farmers collaborating to grow plants that produce color.

Anne de la Sayette , of France, is our keynote speaker. I met Anne when she and Dominique Cardon were co-chairs of the ISEND Natural Dye Symposium, La Rochelle, France in April 2011. Anne created and led the Regional Center for Innovation and Technology Transfer in Horticulture (CRITT) where she initiated and managed a 15-year innovative project on natural dyes. We are very excited to have her here.

Sara Bellows is another of our speakers. She founded Stony Creek Colors in Tennessee She is raising and processing indigo right here in the United States. We are all anxious to hear more about this project.

There will be other speakers and displays. Come and join us if you can. We hope this is only the beginning of a long conversation about growing color here in the mountains of North Carolina and beyond.

Eucalyptus – What’s in the dye?

Eucalyptus is not native to where I live but I have watched dyers (with a bit of envy) from other parts of the world use these plants as a source of color and tannin. Each year I grow a plant or two for experimentation. These experiments have led me to some interesting observations.

The variety commonly found at our local garden center is Silver Dollar Gum (Eucalyptus cinerea). A friend, visiting from Australia, fondly recognized it in the garden as “gummy”. It will grow as an annual here and I always dry the round “silver dollar” leaves for dye. Sometimes I can even acquire them amongst the floral arrangements in the local grocery store. This year I had a additional  variety (Eucalyptus globulus). It was grown by a friend from seeds that she brought from a tree in her yard in Ethiopia.

Dye tests were done on wool, both with and without an alum mordant, using dried leaves at 100% of the weight of fiber. Plants contain many different colorants. In the case of the Eucalyptus leaves, they contain both a flavonol and a tannin. The flavonols are typically yellow in color and require a mordant to attach to the fiber. The tannins  produce a variety of colors and do not require a mordant.

I placed non-mordanted wool fabric in the bath with the leaves. It was brought to a low simmer (approximately 190 degrees F). The color was slow to come but after about 2 hours the Eucalyptus cinerea resulted in a deep red/orange, while the Eucalyptus globulus  turned a deep brown.

Eucalyptus cinerea (left) and Eucalyptus globulus (right) on non-mordanted wool

Alum-mordanted wool was dyed in a separate bath. The fiber quickly (within 30 minutes) turned a brilliant yellow from both varieties of eucalyptus. I removed some of the fiber from the dyebath when the yellow was still bright. As the rest of the fiber stayed in the bath, the tannins were released, changing the color of the wool from yellow to either a deep yellow/orange or a yellow brown. After two hours in the bath the mordanted fiber had been dyed by BOTH the flavonol and the tannin.

Version 2
Eucalyptus cinerea: (left to right) no mordant, 2 hour bath with mordant, 30 minute bath with mordant


Eucalyptus globulus: (left to right) no mordant, 2 hour bath with mordant, 30 minute bath with mordant

Several years ago I heard Michel Garcia say that the clearest yellow color from plants may come at the beginning of a dyebath, before any tannins are extracted. As the fiber stays in the bath with the dyestuff, the tannins are released and the color becomes deeper and duller. The eucalyptus is a dramatic illustration of this principle but other plant materials also indicate the same principle.

Alum mordanted linen fabrics were dyed with small, leafed branches of dyer’s broom (Genista tinctoria). Time in the bath ranged from 15 minutes to 2 hours. The most brilliant yellow was achieved after 30 minutes. After that time the color got deeper and duller, most likely from the tannins released.
Henna, (Lawsonia intermis) which contains flavonols (mainly luteolin), naphthaquinone (lawsone) and tannins: (left to right) mordanted wool 30 minutes in bath, mordanted wool 1 hour in bath, un-mordanted wool 1 hour in bath. The mordanted wool is slightly more yellow than the sample with mordant.

I have not yet completed lightfastness tests on any of these samples but they are in process.  I would guess that the deeper, tannin-rich colors will be more lightfast than the brighter flavonols.

Black Walnut Season


It’s time to collect black walnuts!  The black walnut tree (Juglans nigra) is native to eastern North America.  The outer husk of the nut is the source of dye. The colorant is juglone.  It is a direct dye, which means that no mordant is necessary when used with a protein fiber.  There are some tannins in the husk but that is very secondary to the strong juglone. I have not found a better dye to achieve a rich, fast, brown on protein fibers. Cellulose may be dyed as well, but that requires a mordant.

The best time to gather the nuts is when they are still green: newly fallen or ready to fall off the tree. If the nuts rot and turn black on the ground the dye will be damaged. I preserve the fresh nuts in the freezer for year round dyeing.

I have experimented with drying the nuts carefully on racks to prevent rotting. When I compared these dried nuts to fresh/frozen walnuts in the dyebath it was clear that they contain far less dye. On the other hand, drying may be a practical solution.

Dry walnut vs. fresh: one walnut per 20 grams of fiber.
Increasing the number of dry walnuts deepens the color

I have learned that the secret to dyeing with black walnut is slow dyeing and lots of patience. I put the entire nut(s) in a mesh bag (fresh or dry), cover with water and simmer until the outer skin (the exocarp) breaks open, releasing the soft husk underneath which contains the dye. Then I cool the bath a bit, add the fiber, leaving the entire nut in the bath (in the mesh bag) during the entire dyeing process. The mesh keeps the fiber clean.  I heat the dyebath slowly and leave it for a long time. There were many occasions that I was disappointed in walnut dye, only to finally learn that it takes TIME. I still have to resist the temptation to add more walnut to the bath during the first hour of dyeing, remembering that the dye will get darker with a longer bath.

One fresh walnut was used for  20 grams of fiber. Note the effect of time in the dye bath. Heat was turned off after 4 hours and the fiber remained in the dyebath overnight


2 dry walnuts per 15 grams fiber
1 dry walnut per 20 grams fiber

My typical approach to dyeing with walnuts is to grab a handful of them, making a good “guess” as to how many I need. I decided to approach the dyeing more scientifically in order to control the color and know how many walnuts were actually required to obtain the color I wanted.

A  fresh walnut weighs about 90 grams.  A dry walnut  weighs about 30 grams. The dry nut contains a lot less water and now I know that it also contains a lot less dye.

  • The nut inside the husk (this is the not the dye) =  approx. 20 g
  • A fresh nut contains approx. 70 g of walnut dye material
  • A dry nut contains approx. 10 g of walnut dye material.

I now calculate about one fresh/frozen nut per 20 grams of fiber (or about 350% w.o.f.).  If I am using dry walnuts I will double that amount, at least. Many more dry walnuts will be required to achieve the same color as the fresh walnuts.

Black walnuts are a most versatile dye.  The presence of tannin means that the color can be dulled and deepened with an afterbath of ferrous but when dyed over a deep indigo, a near black color can be achieved on wool or silk without the use of any mordant.

Wool, woven shibori, indigo dyed,  over-dyed with black walnut, textile by Catharine Ellis



Catharine’s new edition of Woven Shibori, focused on natural dye, is available from local booksellers or




WATER: Monday morning bleaching and post-vacation blues

When Joy Boutrup and I were teaching at Penland earlier in the summer she told the story of “Monday morning bleaching”. In old European laundries there was a serious problem with an increased number of holes left in fabrics that were laundered on Monday mornings. During the rest of the week the problem was lessened.


The issue turned out to be iron pipes. Water that had been sitting in the pipes all weekend leached ferrous out of the metal pipes. When ferrous is combined with bleach, the fabric will be compromised, resulting in holes. Once enough water had flowed through the pipes the amount of ferrous was decreased and there was no problem the rest of the week.

I have just experienced a related phenomenon in my own dye studio. After being away from home and studio a week or more, I observed that the water coming out of the studio tap was dark in color. Did this have to do with our shallow well? Was there contamination?

I suspected iron and tested the water for ferrous by stirring a very small amount of gall nut tannin into the water. When ferrous and tannin combine, the water will turn black. This is the principle of gall nut ink, which is made from iron + gall.

A small amount of gall nut tannin was added to both cold and hot water

Water from the studio cold tap was fine. There was no reaction whatsoever. But the hot water turned black immediately, indicating that there was likely a problem with my “on demand” hot water heater. A call to the plumber confirmed that after 10 years of use the heating element had likely deteriorated and the water was leaching iron from the housing of the tank.


I continued to observe the water. After running the tap regularly for two days the iron content was much less but still too dark to be acceptable for dyeing.

After 5 days the hot water seemed to be almost completely clear of ferrous – but not quite.


This was not a good situation for a dye studio and I was forced to use only water from the cold tap for all processes. Yesterday I had a new water heater installed. All water is now completely free of ferrous!

IMG_8927 (1)

Soft acidic water is far more likely to dissolve iron in pipes or other sources. Hard, alkaline water won’t present as much of a problem. My mountain well water is very soft and close to pH 6, which is slightly acidic – the perfect water to leach any metal available. It’s a reminder that all dyeing begins with the water. Some mysteries in the dye studio can be solved by simply looking at the water.