Are All Oak Galls Equal?

The short answer is “no” but here is the longer answer. 

I’ve used Aleppo galls (either ground or extract) for years as my preferred tannin.  They were recommended to me as being high in tannin and are readily available. Gall is a source of colorless, gallic tannin.  I’ve done many tests comparing the Aleppo gall to  tannins, such as sumac (from local leaves), myrobalan, tea, and many others but I had never compared different varieties of oak galls. 

First of all, what is an oak gall?  They are sometimes called “oak apples” and are small, round growths of plant tissue produced by the oak tree in response to the infestation and larvae of a wasp.  There are many different species of wasps as well as oak trees. As a result, the galls from each of these is different. The Aleppo gall nut (Quercus infectoria) is hard and dense but can be ground to produce fine particles.

A friend from Missouri gave me a jar of her local gall nuts. She lives in a forest of white oak (Quercus alba) and gathers the galls when they fall to the ground. These galls have a smoother surface than the Aleppo but are just as hard and dense. 

Recently I was in New England and was able to gather galls from the scarlet oak variety (Quercus cocinea). These are larger, very light in weight, and seemingly hollow. As a child, we referred to them as “puff balls”. 


I wanted to know something about the tannin quantity of these various galls and if they could be used interchangeably for dyeing applications.  They were applied to cotton fabric prior to  mordant and dye. I used each of the tannins at 10% weight of fiber, which is the standard amount I  use of gall nut extract.  

1 gram of each gall source

The whole galls were ground with a small spice grinder, and further crushed using a mortar and pestle. Those from the White and Aleppo oaks broke down into fine granules, while the Scarlet oak variety was impossible to grind as fine, as the insides were truly “puffy” and “spongy”. Each of the ground gall varieties and the extract were put into warm water, using separate beakers for each, along with the cotton cloth.  They sat at room temperature for 1 hour before the mordant was applied. 


I took a portion of the samples with the tannin application and put them into a weak iron bath. When tannin and iron combine a dark grey or black will result. The shade of grey is an indication of the amount of tannin present. The Aleppo gall nuts, in either the ground or extract form, resulted in much deeper shades of grey than either the white or the red oak varieties. The large pieces from the scarlet oak resulted in a very uneven application of tannin. When the iron was applied, the surface was very splotchy and irregular. 

Scan 3
TOP: Tannin only. Although the galls appear to have colorants,  an insignificant amount of color attached to the textile. MIDDLE: with weak iron applicaton.  BOTTOM: sample shows the uneven application of the scarlet oak gall.

The rest of the samples were then mordanted and subsequently dyed with both weld and madder. The amount of tannin has a direct effect on the amount of mordant that can attach to the textile, and the depth of dye color obtained is a direct reflection of the amount of mordant present. Based on the iron applications, I was surprised at the depth of the color obtained with all of the gall varieties. Although the dye color obtained from the white and scarlet oaks is lighter than the Aleppo, there is still significant color attached.

Comparison of various galls with madder and weld dye. Left to right: White oak gall, Scarlet oak gall, Aleppo oak gall, Aleppo extract

When using tannin prior to mordanting, it is likely that increasing the amount of gall from the white or scarlet oaks would increase the amount of mordant that attaches and thus the depth of dye color. 

Locally harvested galls, when available, are an opportunity to use the local resources and achieve acceptable results. 

The Art and The Science of Natural Dyes by Catharine Ellis and Joy Boutrup, available in late fall, is now available for pre-order.

Indigo Harvest in Okinawa

A life of natural dyeing knows no bounds. Each year I am thrilled and delighted to increase my knowledge and understanding of dyes and process. 

This year, I was privileged to participate in the harvesting of indigo and the extraction of pigment on the island of Okinawa, Japan. 

The Okinawa farm has been producing indigo for many years, as evidenced by the large, round concert vessels imbedded in the ground. The vessels are used for extraction of pigment.  Smaller square vessels, also in the ground, are used for the storage of the indigo paste pigment. 

The indigo harvest and extraction is currently being done by a young couple, Takashi and Kitta Sawano. They have been extracting pigment here since 2012.  He is a dyer. She designs and makes beautiful, naturally dyed cotton garments in a studio located in northern Okinawa. The process of harvest and extraction requires many helping hands and there were a number of friends and artisans  who came to get their hands dirty and participate. 

The variety of indigo is Strobilanthes cusia. It looks similar to polygonum tinctorium but this variety requires a hotter climate and has a greater content of indigotin. Even the stems of the plants contain indigo. Eight different harvests are made during the summer season to extract pigment from all the indigo plants.

It was pouring rain the morning we arrived to harvest. I was given a small scythe and some white ropes. I felt somewhat prepared for the cutting and tying process since this is  the same approach that we used last summer when harvesting Polygonum tinctorium at Rowland Ricketts studio/farm. Everything else about the process was different, since Rowland uses his indigo to compost the leaves for sukumo.

The goal was to collect 400 kilos of indigo plant (leaves and stems). Each bundle was weighed and the weight of the wet leaves was taken into consideration. The plants were then tossed into one of the large round vessels that was already filled with water. A porous round tarp had been placed over the surface and the plants went on top of that. The indigo plants were weighted down with wire mesh, boards and rocks to ensure full immersion.  The plants were left to soak for the next 24 hours. 

On the next day, we observed that some fermentation was beginning and measured the pH. 

On the the third day, the fermentation was very active. The plant material was lifted out of the vessel (with the help of a small tractor).  Lime was added. The amount of lime was carefully calculated as too much lime will result in an inferior pigment.  The indigo extraction was aerated for 45 minutes using long rods with a small paddle affixed to the end. The shape of the vessel made this a very efficient operation.



The introduction of oxygen through aeration caused the indigo pigment to precipitate to the bottom of the vessel. Once the excess water was pumped off the surface, the paste pigment could be pumped into a storage container, where a more concentrated pigment will settle to the bottom over the next few weeks. 

I purchase  indigo for use in my own dye vats. Most of it has come from India but I am currently using indigo grown right here in the U.S. at Stoney Creek Colors.  This experience has given me a new appreciation and understanding of the cycle “grow, extract, dye” and a deep respect for those who participate in the entire process.  My thanks go to Hisako SUMI, who has participated in this indigo harvest for the last number of years and invited me to attend –  in the spirit of understanding and sharing. 


Cross Dyeing with Natural Dyes

Cross dyeing: A method of coloring fabrics made from more than one kind of fiber. Each fiber in a fabric designed for crossdyeing takes a specific dye in a different color or in variations of a color.  

… The Fabric Dictionary

As a weaver, I often construct my own textiles before they are dyed. I choose warp yarns,  weft yarns, and then make decisions about how they are going to be fit together. When a fabric is constructed using both protein and cellulose fibers, some dyes can be made to attach only to the wool. Direct dyes, such as black walnut husks, are a great example. When used  on wool or silk, without the use of a mordant, those fibers will dye a deep brown, while any cotton used in the construction of the textile will only be lightly stained or absorb no dye at all.  

This allows me to weave fabrics in white or natural, and then apply the color afterwards, using resists to incorporate design and create layers of color.

Wool, cotton, and silk yarns in the warp.

When indigo in used in combination with a direct dye, the cotton will only absorb the indigo blue.  The protein fiber will absorb some of the indigo, but it is initially a much lighter blue. When overdyed with a direct dye, only the protein fibers will accept that direct dye.

This is an approach I have taken to dyeing my woven textiles for a number of years, ever since I was inspired by a Moroccan belt fabric that used acid dyes to achieve the effects of cross dyeing.

Belt from northern Morocco, woven in wool and cotton, dyed with acid dyes.

When I began working with natural dyes and wanted to do cross dyeing, I was initially limited to the use of direct dyes, such as black walnut husks, lichens or other dyes that did not require a mordant. If a mordant is used, both fibers will dye to some extent. Then Michel Garcia introduced me to the concept of one-bath dyeing.  This is where tannins and acid are used to attach some dyes to a protein, while the cellulose fibers do not dye at all. In effect, the dyes behave like acid dyes. No mordant is required when applying dyes with this process. 

But not everyone is a weaver! Next month I will be teaching natural dyeing for knitters at the first Knitting Getaway at Shakerag Workshops . In preparation, I have been knitting samples that incorporate both wool and cotton. I have added resists, and dyed with combinations of indigo and one-bath acid dyes. This concept can also be applied to knitting yarns that incorporate both wool and cotton. 

It is challenging to identify commercially available fabrics for cross dyeing. I have had fabrics specially woven of wool and cotton for the class that I’ll be teaching at the 11th International Shibori Symposium in Nagoya, Japan. Space is still available in the workshop right now!

cross dye (1)
Silk and rayon, dyed with indigo and rhubarb
cross dye
Linen and silk, dyed with indigo + cochineal rhubarb, madder, and madder.

And on another exciting note: The Art and Science of Natural Dye will be published by Schiffer Publishers in the fall and is now available for pre-order from Schiffer or Amazon. In fact, I just finished the last of the copy edits today!

Art and Science of Natural DyesArt and Science of Natural Dyes back


Indigo Dyeing: Time and Patience

Learning about indigo continues….

I often receive questions about indigo dye that fades very quickly on a textile. When I ask the dyer how long the textile was immersed in the vat the response is usually “1 or 2 minutes”. That is not enough time! Each immersion in the vat needs to be long enough to permit the indigo to penetrate into the fiber: at least 10-15 minutes. Otherwise the dye simply sits on the surface of the textile, making it susceptible to fading and rubbing off.

Recently, I completed a series of tests in which I experimented with much longer immersions in the vat. Immersion times in the vat ranged from 20 minutes to 20 hours. A longer dip encouraged more dye to penetrate the fibers. The results are worth observing and discussing. All samples were neutralized in a vinegar/water solution and “boiled” to finish and remove excess dye.

indigo and time
Indigo on cotton, silk, and wool, each with a single dip in the vat

The most common method of achieving dark colors with indigo is multiple successive dips in the vat and there are definitely some advantages to building color in this way. Any unevenness of the dye will level out as the textile is immersed multiple times. This is  especially important  when dyeing large textiles in a small vat. (This is the reason why larger vats are better suited when dyeing large textiles; allowing the dye to reach more of the textile surface)  If the vat is large enough that the textile can be immersed and exposed evenly to the dye, longer immersion times may be a practical approach.

multiple dips
Indigo on cotton, silk, and wool with multiple (1-6) 15 minute dips
time exposure 2
Fabric woven of wool and cotton yarns. After a single 20-minute immersion, the cotton fiber is darker. After 2 hours, both fibers are close to the same color. After 18 hours, the wool has absorbed a great deal more indigo while the cotton has maxed out. Multiple dips in the vat are required to achieve very dark blues on cotton.

My usual approach to dyeing textiles is using woven shibori. The textile is gathered with the woven “stitching” threads, making a compact “package”, and exposing the outside pleats of the textile to the dye uniformly.

indigo, dobby weave
Cotton, woven shibori, multiple indigo dips

Lately I have been experimenting with itajimi shibori (folded and clamped resists), where many layers of cloth might be folded multiple times. When using mordant dyes or fiber reactive dyes, the dye usually penetrates through the layers. When dyeing with indigo (10-20 minute immersions), the dye fails to penetrate beyond the outside layer and into the cloth within the folds, despite multiple immersions. When the immersion time was increased to 24 hours the dye penetrated ALL the layers – like magic. More time in the vat allowed complete penetration of dye throughout the textile.


Lightfast tests were performed on all samples dyed with extended times in the vat by exposing 1/2 of the samples to four weeks in a window with direct sunlight.


Note: When dyeing protein fibers, care must be taken with the pH of the vat, as the fibers can be damaged by long exposure if the pH is too high. Ideal pH for protein is 9.5-10. 



The North Carolina Arboretum is hosting the second Growing Color Symposium on March 8, 2018. Michel Garcia will be our keynote speaker. Join us if you can!

Re-visiting Local Plants.

Last week I was a student in a class with local dyer, Dede Styles, at Cloth Fiber Workshop. Dede describes herself as a “heritage dyer”. She learned the craft from Mary Frances Davidson, another heritage dyer from our North Carolina mountain region, who wrote a book on the local dye plants. The Dye Pot, originally published in 1950, is still in print today.

Dede discussing her naturally dyed yarns

Dede dyes mostly wool and uses only local plants that she can collect herself (with the exception of cochineal and indigo which do not grow here). Her knowledge of plants, local water sources, and seasonal growing patterns is exceptional. The dye plants she uses are very specific to this part of the country, though some are found in other areas.  They are chosen because they give good color that lasts.

She carried buckets of her own “creek water” to the workshop rather than use city water from the tap and described how she can obtain a certain color with a particular dye using water from her creek.  Water from “over the mountain” will produce a very different hue.

Dede dyes yarn in quantity, outdoors, using large stainless steel, iron, or copper pots. Her philosophy about dye amounts is to “cram as much dye plant material as possible into the pot”.  After cooking, she strains the liquid. All the yarn for a certain project must be dyed at the same time in a single dye-lot since results are not exactly repeatable. As someone who measures everything carefully and precicely, this is a refreshing approach.

Fall is a good time to gather local plants. We observed what was growing around the weedy area near the railroad tracks, paying special attention to stands of goldenrod, sumac, and fall asters.  Dede knows a lot.  She told us that many people think they are allergic to goldenrod, but the ragweed that grows nearby is really the source of the allergens – goldenrod is only pollinated by bees, thus there is no airborne pollen! The white asters seem to produce more color than the purple fall asters, says Dede – likely because the purple asters grow in damper areas – and maybe the dyestuff is diluted. She pointed out the difference between sumac and the similar looking Goldenraintree, which contains no dye.  Some plants are biennials and thus will only be found growing in the same area on alternate years. As we walked, Dede talked about responsible gathering of plants, and the damaging use of herbicides by roadsides and railroad tracks.  Gentrification, she says, is the enemy of wild dye plants. Springtime, when the tree sap is running,  is the only time to easily gather bark from a fallen tree.  And of course, she wanted to be sure we knew the difference between Virginia creeper and poison ivy – neither one of these is a dye plant but they are often found growing together in the same vicinity as the dye plants.

I hope that there are more “Dedes”  out there where you live  – people who know their plants from deep experience and observation and who are willing to share what they know. We owe it to ourselves to honor them and to learn from them. Dede told us that she is working on a book. It will be about the local Western North Carolina plants: where they grown, where to find them, and when to gather them responsibly.

Thank you Dede!

And a follow-up to my own earlier experiments with some locally gathered dyes – flavonoids. Some of them came from my garden (coreopsis, broom, chamomile, marigold, and weld) others from “the field” (black oak bark and goldenrod) and a couple were purchased (osage and Persian Berries). I dyed mordanted silk and subjected them to lightfastness tests. The weld from the garden will continue to be my “go-to” yellow dye.

Flavonoid dyes after 3 weeks exposure to direct sun


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

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.


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.

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.


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.

What is Local Color?

Most of us working with natural dyes have no immediate tradition from which to learn or elders to teach us. We are re-inventing natural dye, trying to learn from books, teachers and other dyers who are willing to share what they know and, of course, our own experiences and mistakes.

Many of us purchase our natural dyes from suppliers in the form of extracts or dyestuffs that are grown and harvested in other parts of the world. In this way, we can access all of the classical dyes, such as indigo, madder, cochineal, weld, pomegranate, etc. These dyes do not necessarily reflect where we live or where we come from.

I was in Madagascar for two weeks during May for the International Festival of Plants, Ecology and Colors. Following the conference our small group spent time in a  village in the northwest deciduous region. There we saw women harvest raffia from the local palm trees and wild silk from cocoons in the local mangrove forest. Natural dyestuffs are gathered in the immediate surroundings and are coaxed from the leaves, barks, resins, and fruit of local plants. The ONLY dyes available are truly local dyes, which the dyers gather themselves and about which they possess a deep knowledge of experience. Most of the plants used for dyeing are also used medicinally. Importing dyestuffs is not an option here.

Peeling away bark from tree (Hiragana madagascarensis). Bark is taken from one side only, in order to keep the tree healthy.

The  region is rich with sources of natural color, including reds from teak leaves, indigo from the local Indigofera erecta, gold and yellow from barks, and black from tannin and iron-rich mud. Wood ash and citrus fruit provide adjustments in pH when needed.

My own local environment does not have such range of color available in “the wild”, though I do maintain a garden of dye plants. I came home from this trip with a deeper understanding of what LOCAL color really means and now have a new resolve to identify local dye sources from my own immediate environment. No doubt, they will be variations of a yellow color since plants containing flavonols and tannins are in abundance.

Local raffia, dyed with local plants
lac % 6
Raffia weaving: red dyed with teak leaves, brown from tannin and iron rich mud, blue from fresh leaf indigo.

I have already begun the dye experiments in the search of my own “personal colors”. All of the dyes will be put through rigorous testing for light fastness and wash fastness. In the end, I hope to identify one or two dye sources that are abundant and easy to harvest here in western North Carolina. Of course, collection of these plants must pose no threat to our environment.

local plant tests
Initial tests of local plants on silk with alum mordant and post mordant of ferrous acetate. Garden dye plants included for comparison.

I’ll report back once the testing is complete.