Mordants

Black: An Improvisation

~ Catharine Ellis ~ 31 Comments

I recently took on a small weaving commission that required the use of black wool yarn. For a brief moment I contemplated purchasing the wool in the required color and then decided that I could dye it. I was surprised at how easy it was to achieve a rich, deep black color on the wool using only indigo and madder. 

Commissioned weaving using wool yarns dye with indigo blue, madder red, black from indigo and madder

It inspired me to continue my current series of color studies, woven in cotton and linen, with an in-depth exploration of black dyes. 

Initially, I wanted to achieve all the black hues without the use of an iron mordant. My years of mixing hues with primary colors gave me the confidence to believe that I could mix a good black for cellulose using 3 primary colors: blue, red, and yellow. The key was going to be finding the correct proportions. 

The first step was to build up a deep layer of indigo blue (usually 8-10 dips in the vat) followed by a mordant, and finally red and yellow dyes. That red could be madder or cochineal but I chose to use only madder, since that is what I am growing in the garden.  My preferred yellow is weld.  Each different combination results in a subtle variation. Some “blacks” are more purple, while others are a bit more green, or brown. I began using black walnut  and cutch as a substitute for the madder and weld and sometimes added madder or weld to those.  Each is a distinct hue, and definitely in the “black” family. I am confident of the lightfastness of these hues because of the primary dyes that have been used. 

Dark indigo alone, on far left + combination of cutch and madder resulted in a neutral black
close up of “black” hues in the series on cotton and linen fabrics

These multiple shades of black, put me in mind of the paintings in The Rothko Chapel in Houston, which is the site of a series of large large “black” canvases by the artist, Mark Rothko. These black canvases are painted with layers of crimson, alizarin, and black.

But no exploration of black would be complete without some experiments using tannin and iron. Instead of building up layers of primary colors, I soaked the textile in a gall nut tannin bath, followed by a short immersion in an iron bath. I wanted to use as little iron as possible, but still achieve a very dark shade. I decided that 3% weight of fiber would be the limit of the amount of iron I would use.

Most often, I use ferrous acetate instead of ferrous sulfate because it is less damaging to the fiber. Cellulose fibers are are somewhat tolerant of ferrous sulfate so I did experiments with both. That is where I was most surprised! Without exception, the ferrous acetate resulted in deeper colors than the same amount of ferrous sulfate. 

Why? I wasn’t sure. So I consulted my colleague, Joy Boutrup, who always knows these things. 

“I think the reason for the grey instead of black with iron sulfate is due to the higher acidity of the sulfate. The acetate is much less acidic. The  tannin complex cannot form to the same degree as with acetate.”

The pH of my ferrous sulfate solution was 4. The ferrous acetate was pH 6. (My tap water is from a well and is a slightly acidic pH6.)

The grey and blacks achieved with the tannin and iron are quite one-dimensional compared with those that result from a mix of colors and not nearly as interesting, Yet they are likely a more economical approach to achieving black; the multiple indigo dips, mordanting, and over-dyeing takes considerably more time and materials than an immersion in a tannin and an iron bath. 

Always observing always learning, here in the mountains of North Carolina…

Studio image of completed woven panels

Symplocos – A Plant Mordant

~ Catharine Ellis ~ 51 Comments

Symplocos is a plant species that accumulates alum mordant. It is one of number of plants that grows in acidic soil around the world, and thus is able to absorb available aluminum from the ground. Although different parts of the tree absorb alum, it has been determined that the fallen leaves have a high concentrations of alum and are the most sustainable source of mordant. By harvesting the fallen leaves, no damage is done to the tree. These leaves can be used as an alternative and highly effective source of mineral alum, while also imparting a pale yellow color to the fiber. 

One variety of symplocos is native to Indonesia and utilized by weavers and ikat dyers with when dyeing red with morinda (Morinda citrifolia) on cotton. The Bebali Foundation has been studying the mordant process for a number of years and has made symplocos available to dyers around the world, while supporting the local women who gather the leaves. Michel Garcia worked with the foundation to develop recipes for both protein and cellulose fibers. All of these recipes are available online at The Plant Mordant Project.

I have experimented with symplocos many times with great success. Recently I have been introduced to a variety of symplocos  (Sympolocos tinctoria)  that is native to the southeastern United States. It is described as a small tree or shrub, “deciduous or weakly evergreen”. It is also known as “horse sugar” or “sweetleaf” because horses are attracted to the sweet leaves of the plant. As I researched, I read that it grows in “very acidic soils”. It is sometimes described as a source of yellow dye, but nowhere did I read that it was a source of alum. 

The symplocos tree
Distinct blossom of the Symplocos tinctoria will help identify the plant

Leigh Magar, a textile designer and dyer, brought me a handful of leaves last year that she collected at her home near Charleston, South Carolina. I proceeded to test the leaves as a source of mordant, comparing them to the symplocos that I have from the Bebali Foundation, and also to mineral alum. I ground the leaves and used Michel Garcia’s recipe. The results were very good. 

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Mordant only applied to wash-fast wool knit: 1.) no mordant, 2.) mineral alum mordant, 3.) Bebali symplocos mordant, 4.) South Carolina symplocos mordant

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Weld and madder dyes applied following 1.) no mordant, 2.) mineral alum mordant, 3.) Bebali symplocos, 4.) South Carolina symplocos

sympolocos leaves
South Carolina leaf on left, compared to the larger symplocos leaf from Bebali. Both leaves were ground fine before applying them to the textile.

Last month I was finally able to travel to Leigh’s home in South Carolina to see the plants myself and to gather some of the leaves. Our regional variety has leaves that are smaller than the Indonesian variety but they are shed in much the same way. The leaves yellow as they age and drop from the tree. They are easily gathered from the tree at this time. Leigh tells me that shedding seems to be more more prevalent in the spring, although the tree sheds its leaves all year long.  

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Older leaves yellow on the tree before falling to the ground

I am currently reading (and very much enjoying) Braiding Sweetgrass by Robin Wall Kimmerer. In the chapter entitled The Gift of Strawberries the author talks of wild strawberries as unexpected gifts received from the earth. Finding alum in a plant is very much like a gift – to be received gratefully – but not to be turned into a commodity. I will treasure this gift of alum and appreciate Leigh’s generosity in sharing it,  but it will not replace the mineral alum that I purchase from a supplier.

symplocos leaves beneath the tree
gathering leaves

gathering leaves
symplocos leaves beneath the tree

And a couple notes on our book: The Art and Science of Natural Dyes. First of all, I am very appreciative of the many notes and emails I have received from so many of you. It is exciting to both Joy and me that the book is finally out and truly being used. 

There is one important omission on pages 169 and 170. The mordants used for the photos of the dyed samples should cross reference mordants #1 – #5 (top to bottom), from the mordant mixing chart on p.150.

p 169 corretion

And about the spiral binding – we chose the binding very intentionally so that the book would open easily and stay open. The book is meant to be used, referred to, and likely to get stained, like a much used cookbook. Many of you have told me how much you love the binding but I have also heard from a few of you that pages can easily slip out of that spiral. A dyer in Australia showed me a perfect solution; she threaded a piece of cotton yarn through the binding, locking the pages in. I have now done this to my own book and would suggest that you do it to yours as well. 

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Alum in the dyepot? How do YOU mordant your textiles?

~ Catharine Ellis ~ 13 Comments

My first experience with natural dyeing occurred many years ago. My first teacher, Mabel Myers, was a Navajo weaver who taught at Navajo Community College in Arizona (now called Dine College),  where I was studying for a year during college. After spinning wool for my first rug on a long Navajo spindle (my first spinning), we went to the Lukachukai Mountains, where we gathered some leaves (I don’t know what kind) and white, powdery alum from the ground. When I asked Mabel how she knew that this was “alum” she took a taste. That’s how she knew!

We returned to the classroom. The  yarn, leaves, and alum mordant all went into a dyepot and cooked for a while. We obtained brown, gold, and orange colors. The hues were deep and rich and they are still in that wool today, nearly 50 years later.

 

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My first natural dyeing with unknown plants

Since that first experience with natural dyes I have learned a lot about dyeing. Now I know that the BEST method of dyeing is to apply the mordant first, and then the dye,  after rinsing out any excess mordant. This is the approach used by professional dyers and in industry. It is the most economical use of both dye and mordant. When mordant and dye bind together, preferable IN the textile, an insoluble compound is made, called a lake. If mordant and dye go into the dyepot together, some of the mordant and dye will bind together in the bath before ever having a chance to penetrate inside the textile.

While in Madagascar last month, I watched dyers add bark (the dyestuff), raffia (the textile), and crystalized alum (the mordant), to the dyebath all at the same time. My “professional dye knowledge” told me this was not the best approach. But then I began to think.

All of the dyeing here was done over a small wood fire. Wood is scarce. Madagascar is a seriously de-forested country. Charcoal is still made regularly from wood and used for nearly all cooking. The women were very skilled at controlling temperature by increasing or decreasing the amount of wood on the fire or moving it closer or further away. Perhaps the process is optimized to conserve the most valuable resource: the fuel.

small bundles of charcoal in the market
large bags of charcoal in the market

Maybe time is the most valuable resource. The women worked together but their dyeing activity went hand-in-hand with childcare and there were many small children around, observing and participating when appropriate. When everything goes into the pot together the dye process takes less time.

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Or maybe the dyepot itself was the most valuable resource. I only saw two pots. Pre-mordanting would require not only a single use of a pot, but might also necessitate the storage of mordanted textiles while they awaited dyeing.

Exposure to dyers in different parts of the world causes me to have a more open mind about process. It encourages me to think more about what I am doing and why I do it. The “BEST” process is not always best for everyone.