The Effect of pH on Yellow Dyes from the Garden

June 23, 2020September 24, 2020 ~ Catharine Ellis ~ 25 Comments

yellows on line

First of all, I know that my well water is acidic. It measures about pH 6.0 here in the mountains of North Carolina. The water is ideal for most dyeing. There is no iron or other minerals that might dull the colors. The acidity is another issue.

Most of the yellow dyes in my garden, or those that I might gather locally, are flavonoids. That means that they require a mordant in order to attach to the textile. No mordant means no yellow. It’s that simple. Some of the dyes may also contain some tannin or other colorants but the yellow is what we’re talking about here.

Last summer Joy Boutrup and I taught a class together at Penland School of Crafts, located near my home in western North Carolina. A student in the class was especially interested in gathering local plants for use as a dye source. She struggled to get the locally gathered dyes to attach to her textiles, especially onto mordanted cotton.

Joy had the answer-of course!

When the dye meets the mordant in a textile, an insoluble lake is formed. This lake is formed most readily in neutral or slightly alkaline conditions.

An alum mordant makes a very strong bond with wool but there is no chemical bond between cellulose and the mordant. Instead, the mordant is deposited as an insoluble compound on the textile.

An additional issue is that many of our local plants are acidic. When the plants are boiled in our already acidic water, the pH of the dyebath becomes so low that the dye may struggle to attach to the mordant in the fiber. In fact, the mordant in the cotton can be damaged or even removed if the bath is acidic enough. This is exactly the reason why we don’t add an acid to a cochineal bath when dyeing cellulose. The mordant would be damaged and little dye attaches.

The remedy: Add a small amount of chalk (calcium carbonate) to the dye bath to neutralize the acid that is present. This will do no damage to the dye or the textile. Chalk is not an alkaline but will neutralize an acid that is present. Within reason, there is no possibility of having too much chalk and any excess will simply precipitate in the bath and rinse out of the fabric

Since my own broom (Genista tinctoria) is currently in need of a serious trim, I began a series of flavonoid dye tests with that and then compared other dyes from my garden and environs.

Broom is currently blooming in front of my studio

Broom, with and without chalk

I used all fresh plants at 300% w.o.f. and dyed both wool and cotton. The wool was mordanted in alum. The cotton was mordanted using tannin plus alum and soda ash. After making the dye decoction, I divided the dye bath in two equal portions and added both wool and cotton to each bath. Chalk was added to only one of the baths.

The results were quite surprising (but also very consistent) and made me realize that I have likely not been achieving the maximum amount of color from some of my local dyes.

The plants I gathered and used were

- Broom (Genista tinctoria)
- Wild grape leaves
- Apple leaves
- Dyer’s Chamomile (Anthemis tinctoria). I used the flowers and after gathering a basket of the small flowers I tested the dye content in the entire plant.
- Staghorn sumac (Rhus typhena) . We often think of sumac as a good source of tannin but the leaves, according to Dominique Cardon, are also rich in flavonoids.
- Weld (Reseda luteola). This is my “go-to” yellow dye. I almost always use dried plants and I rarely add chalk with weld on cotton but frequently add it to a wool bath.

After boiling the plant material I recorded the pH of the decoction. The pH was measured again after the addition of chalk. Each dye bath was approximately 4 liters and I added about 1 TBS of chalk.

The chalk will alter the appearance of the bath from transparent to cloudy and nearly opaque.

weld in pot w/wo chalk — Weld baths: no chalk on left, chalk added on right

plant	pH after boiling	pH after addition of chalk
Dyer’s broom (Genista tinctoria)	5	6
Wild grape leaves	4	6
Apple leaves	5	6.5
Dyer’s chamomile (Anthemis tinctoria) (flowers)	4.5	6.5
Dyer’s chamomile (Anthemis tinctoria) (whole plant)	4.5	6.5
Staghorn sumac (Rhus typhena)	4	6
Weld (fresh plant) (Reseda luteola)	5.5	6.5
Weld (dried plant)	5.5	6.5

The samples below are wool. Individual samples on the left had chalk added to the bath. Those on the right did not.

Apple leaves

Grape leaves

Fresh weld

Dried weld

Sumac leaves

Dyer’s chamomile, whole plant

Dyer’s chamomile flowers

Broom, with and without chalk

In every case, I achieved deeper and brighter yellows colors when the chalk was added to the fresh plant baths. The only exception was dried weld, which was used at 50% w.o.f. When dyeing with the fresh weld plants, deeper yellow hues resulted with the addition of chalk. When I used dried weld plants, the chalk made very little difference. I asked Joy about this and she indicated that is was possible that some of the acids disappear in the drying process. It will require more tests and explorations to confirm this.

The cellulose samples are especially notable. The high acidity of some baths made without the chalk was enough to damage the mordant significantly. The grape leaves and the sumac, which were the most acidic, destroyed the mordant in the cellulose and only the tannins that are present in the leaf were able to attach and color the fabric.

cellulose no chalk — Palette of color on cotton without the addition of chalk. Left to right: Chamomile flowers, broom, apple leaves, chamomile (whole plant), weld, sumac, grape leaves

cellulose with chalk — Palette of color on cotton with the use of chalk. Left to right: Chamomile flowers, broom, apple leaves, chamomile (whole plant), weld, sumac, grape leaves

If your water is not acidic, or has calcium in it, then these tests may not be relevant but the addition of chalk will never harm the fiber or the dye and may release more color.

I recently found the following note that I had made during a class with Michel Garcia several years ago referring to grape leaves:

“If they are too sour they will dissolve part of the mordant.” M. Garcia

My own notes continue to say:

After boiling the grape leaves the solution of a pH 4 – too acidic – it will remove the mordants. Sumac will cause the same effect. Boiling breaks the bonds of the tannins and gallic acid is released. Add chalk to the bath to decrease the acidity of the dye bath – you cannot be in excess of chalk.

Sometimes we’re just not ready to absorb information the first time we hear it. This is exactly why I continue to question, keep notes, and actively test and observe.

It’s summertime! Enjoy your yellow flavonoids!

Note: I purchase my chalk from a potter’s supply store. It is inexpensive and can be purchased in quantity. Potters refer to it a “whiting” and rarely refer to it as chalk or calcium carbonate. Do check the MSDS though, just to be sure.

Upcoming: On July 13 I am presenting a Zoom webinar, entitled Colors from the Garden, as part of the John C. Campbell Folks School’s Appalachian Traditions Series. You can sign up here:

Re-visiting Local Plants.

October 13, 2017November 10, 2019 ~ Catharine Ellis ~ 8 Comments

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.

Various dye plants, gathered locally

Dede Styles with yarns dyed with Black walnut bark

Straining sumac berries through a cotton cloth

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.

Black walnut bark. Saplings are plentiful where the nuts have sprouted and need to be cut down regularly.

Goldenrod and white fall asters

Bumper sticker on Dede’s van

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

What is Local Color?

June 1, 2017November 10, 2019 ~ Catharine Ellis ~ 27 Comments

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.

P1100713 — 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.

Inner bark of sapling (Acricocarpus excelsus) used for dye

Wood ash is added to the bark dye. As the ash is added the color deepens and reddens.

Resulting color after the ash has been added

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.

Raffia dyed directly with indigo leaves (Indigofera erecta)

Direct indigo dye (no vat) is the source of blue and purple. Yellow from bark of Hiragana madagascariensis.

P1100551 — 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.

Dyes from the Local Food Co-op

July 4, 2016November 10, 2019 ~ Catharine Ellis ~ 3 Comments

I welcome the opportunity to teach a workshop, especially when it will teach ME something new.

A few days ago I taught Dyes from the Local Food Co-op at Cloth Fiber Workshop in Asheville. The class came about when I was measuring some herbs and spices at our local food co-op. I noticed that a number of the dried materials in the glass jars were the same as the dye plants I was using in my studio: buckthorn bark, annatto, chamomile, and dock root. Obviously, the co-op was not stocking these substances for dyers, but….. it caused me to think about the multiple uses of these plants. For many years I have been taking a tincture of Isatis tinctoria, or WOAD, prescribed by my Chinese medicine doctor. How much overlap would I find between the dye and culinary/medicinal plants?

After taking an inventory of the materials available at the local co-op I decided on a collection of plants for this class. The criteria for the dyes included the following:

Each plant has some historical reference as a dye plant, and is preferably included in Natural Dyes: Sources, Tradition, Technology, and Science by Dominique Cardon.
Each has an alternative use, such as medicinal or culinary.

St. Johns Wort dye

“finishing off” the dye process

Bloodroot dye

Mahonia

samples ready for cutting

Not all of these dyes are excellent performers. For reasons of poor light fastness or wash fastness I would not choose to use many of them in my regular studio work. But each dye has a story and may have been used throughout history because of its striking hue, availability, and/or affordability, despite a poor performance as a color over time.

Some of the dyes have been assigned a Natural Color Index Number (CI#). This is a reference database of color hues, names, and products maintained by the Society of Dyers and Colorists and the American Association of Textile Chemist and Colorists. It includes both synthetic and natural pigments. The inclusion of these natural colorants confirms the important historical reference and unique quality of their colors.

ferrous acetate comparison – photo by Kimberly Coyne

Sassafras bark – photo by Kimberly Coyne

fermented buckthorn bark dye, photo by Kimberly Coyne

Our dyeing was done on silk fabric. Some dyes required mordants, while others did not. Some roots and barks required alcohol extractions, while others extracted in water. Some dyes were affected by alkalinity. Others contained tannins and were altered with ferrous acetate. Alternative sources of the same plant resulted in color variations, suggesting that different parts of the plant were used, or possible changes in the growing season or drying process. When appropriate, we used alternative methods of dyeing such as a one-bath acid dye or fermentation.