July | 2016 | Natural Dye: Experiments and Results

This summer took me to the Textile Center in Minneapolis, where I was invited to have a solo exhibition of naturally dyed textiles entitled Natural Dye: Experiments and Realizations. The title pretty much sums up the way I work: testing, experimenting and finally bringing it all to a conclusion before beginning the next set of investigations.

Version 2 — Natural Dyeing: Experiments and Investigations

The Textile Center in Minneapolis is a nucleus of textile energy. Also at the galleries this summer is The Power of Maya Women’s Artistry, a stunning collection of hooked rugs made by women in Guatemala using recycled cotton materials. Mary Anne Wise, the Wisconsin based rug designer who got this project started a few years ago, will be speaking at the Textile Center today, July 21, and a workshop will follow this weekend. The third exhibition on display is Naturally: A Natural Dye Invitational, which is a lively collection of eco-printed textiles done by members of the Minneapolis textile community.These exhibitions will remain in the galleries all summer.

Michel Garcia was at the Center last week as the first Margaret Miller Artist-in-Residence, a residency named for the founding director of the Textile Center. Michel taught two fully enrolled classes: Color From Plants, A Natural Dye Workshop and Natural Indigo Dye Vat. I had the opportunity to sit in on a day of the natural dye workshop. It happened to be the day the class was working with cotton.

Over the last few years I have had several opportunities to learn from Michel in both workshops and filming sessions with Natural Dye Workshop and Slow Fiber Studios. Each experience brings me a clearer understanding of process and I can never predict what I will learn.

Version 2

Michel is a philosopher as much as a dyer and chemist. He invites us to think about chemistry, process, and cultural ideas – all at the same time. It is stimulating, hard work to sift through all that he shares. One is not always ready to hear his messages. During this day, I began to get a glimpse of the way in which mordants may be affected (and damaged) by both acids and alkalines.

The next step for me, after being in a workshop with Michel, is always to go home, experiment, and really learn the lesson for myself. I have been trying to grasp the reasoning behind sequencing of dye colors with indigo. Years ago I learned to make greens and violets by dyeing indigo over yellow or red dyes. In 2011 I heard Michel Garcia state that the indigo should always be dyed first. Only then should the cloth be mordanted and dyed with another color. But I continued to work as I always had for a while – it’s sometimes difficult to un-learn what we think we know!

Over time I began observing that when indigo was dyed over a yellow or a red, the initial brilliant green or purple often becomes duller as the indigo dye is neutralized. If indigo is dyed first, and other colors dyed over the blue, the colors remain stable. WHY? Is the mordant damaged? Is the dye damaged? Is the alkalinity of the indigo vat the culprit? Is it the vinegar bath that is used for neutralizing the problem? It’s a subtle difference but one that I was very aware of.

I made these observations on cotton, but does it hold true for all fibers?

Cotton and ramie: the sample on the right definitely is a brighter green, when the indigo was dyed first, followed by tannin, mordant, and broom dyebath.

I wanted to test both protein and cellulose fibers that were mordanted. Instead of using indigo, I would simulate the alkalinity of an indigo vat by putting a similar amount of lime (calcium hydroxide) in water. As with indigo, I would also neutralize the cloth in vinegar after it had been in the lime bath. All samples were initially mordanted at the same time and dyed in the same dyebath. Sample #2 was dipped in an alkaline solution prior to dyeing. Sample #3 was dipped in the alkaline solution after dyeing.

cotton dyed in weld

silk dyed in weld

from top to bottom

#1. Mordant, dye
#2. Mordant, dip in alkaline solution, neutralize in vinegar, dye
#3. Mordant, dye, dip in alkaline solution, neutralize

What I observed consistently on both cotton and silk is a lighter dye color after the mordanted fiber had been put in to the alkaline solution (sample #2), which would indicate that the mordant had been compromised. When the fiber was put into the alkaline solution after dyeing (sample #3) the final color was brighter than #2, but not as brilliant as #1. This brightening would be consistent with a calcium or chalk treatment of weld in the dyebath.

Wool was a slightly different story. In the past I have not observed there to be major color differences when layering colors with indigo on wool. Mordants attach to wool in a different way than on cellulose and even silk, which leaves the mordants less susceptible to damage by the alkalinity of the indigo bath.

Wool, dyed in madder

Wool, dyed in cochineal

from top to bottom

#1. Mordant, dye
#2. Mordant, dip in alkaline solution, neutralize in vinegar, dye
#3. Mordant, dye, dip in alkaline solution, neutralize

In the wool samples, #2 was nearly identical to #1. The alkaline treatment of the dye in #3 is consistent with the effect of pH and calcium on either of these dyes.

Conclusion: the mordant on cellulose and silk is very likely damaged by the alkalinity of the indigo vat. In my own practice, I had already shifted my sequence of colors when using indigo in combination with other dyes. Now I believe I understand more clearly why it is important. Cellulose and silk fibers, especially, should always be mordanted AFTER dyeing in indigo. Both the tannin and mordanting processes are acidic and will assure a thorough neutralization of the alkaline from the indigo. Although it may not be as important with wool, this same sequence may give the dyer more control over the final color.

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.