New Inspirations and Lessons

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.

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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.

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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.

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.

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.

13 thoughts on “New Inspirations and Lessons

  1. Hi! I just bought your book, even though I’m a wet felt artist a knitter. I still consider myself new to natural dyeing, even though I’ve been doing it for 4 years. I did notice that the indigo seems to “fall off” or fade away, after a few years, if overdyed. Thank you for sharing this chemistry.

  2. I am not sure if it is the mordant process that is compromised or the sericin that is being pulled out of the silk that causes the lighter color. If the silk were scoured in an alkaline solution before mordanting, that might pull the sericin out prior to mordanting and allow the process to be the same. I have asked silk experts and there is some amount of sericin left in all silk which would dye in the first dye bath and then be removed by the alkaline bath …..

    1. The silk I used was well scoured and didn’t seem to have any residual sericin, yet it’s always possible that there is some undetected sericin left in the fiber. Even if that were the case, it still leaves us with a good reason to dye with the indigo first, so that the other colors aren’t diminished. Thanks!

  3. Hi Catharine, as usual I am so impressed by your tenacity and hard work to learn more about the nature of natural dyes and mordants. You are such an inspiration, and a great example and mentor to the rest of us. I have also had similar experiences with post dyeing with indigo on both commercially dyed and naturally dyed cotton and silk which I printed with the clay resist paste first, then put into the indigo vat. It appeared as though 50% of the base colour was lost after putting into the indigo vat, so now I always dye with indigo first. Thanks for your informative post.

    1. Thank for your comment Julie. I’m glad to know that you’ve experienced the same thing. I’ve been so disappointed in the past to watch lovely grassy greens turn to dull blue greens when the indigo is dyed over the yellow. Now that I am accustomed to dyeing with indigo first it’s an easy fix but it took a while to get there. Understanding “why” is the key!

  4. Thank you for your well thought out premise on mordanting AFTER the indigo. I’m pleased to have been able to see your exhibit and to have met you at the Textile Museum. I’m relatively new to the botanical dye world and was intrigued by your dye combinations (and purchased your book just for the dye information). I’m now experimenting with the dye combinations with indigo combined with the mordanting process, so I appreciate your insight!

  5. Your blog is very helpful. I have been experimenting with fermenting various plant materials other than lichens or indigo to make a dye bath.

    Have you tried this method?

    Thank you for your sharing of information. Frances

    1. I have done some fermenting, based on the work of Krista Vajanto in Finland. She presents a very interesting premise of attaching a tannin dye over time. It has proven to be very lightfast as well. Riihivilla has a great blog that talks about this approach to fermenting dyes.

  6. As usual you lead us thru dye complexity with simple statements, thank you for providing your view into Garcia’s teaching thru your experiments. Another journey to contemplate at the dye pot! Deb Mc

  7. Thank you Catharine! I had a note from my workshop with Michel 2 years ago about dyeing with indigo first, and thought I had misunderstood!
    I so appreciate your clear and generous research and explanations!

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