Book is out! & Teaching at Penland


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On the shelf at the Penland Supply Store – photo by Debra Frasier

Woven Shibori has been printed and is on the shelves of your favorite bookseller (also available at Amazon).  I had some of the first copies delivered to me while teaching natural dye with Joy Boutrup at Penland School of Crafts. It was a fitting place to receive the first books. Joy has helped me over the years to understand the chemistry of natural dyes, various finishing processes, and textiles in general. I could not have completed even the first version of Woven Shibori without her input.


Catharine and Joy at Penland  –  photo by Robin Dreyer

I love teaching at Penland! The studios are beautiful, thoughtfully cared for, and well supplied.  Our students were fabulous and ready for whatever we brought to class. We focused on experiments, observations, and clarifications. The class worked with all natural fibers, and processes included dyeing, printing, and discharge. We were focused on WHY things happen rather than simply how they are done.

Every time I teach with Joy, I  walk away feeling that I’ve taken a  a class as well. We learn from each other as we solve problems, observe results, and identify the best practices for the studio.

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So here is one of the things that FINALLY became clear to me.

I’ve heard/read for years that if animal hide glue was added to the indigo vat, then it would be better for wool or other protein fiber. But WHY? That had never been explained. Did the glue coat the fiber in some way?

The organic sugar vats, that I learned to make from Michel Garcia, use sugars from fruit or plants to create the reduction. Lime (calcium hydroxide) provides the alkalinity.

The vat begins with a quick reduction that eventually becomes a fermentation vat. These vats require a very high pH (about 13-14) in order to start the reduction. If the pH is too low the vat will not reduce. But it does not need a high pH to stay in reduction or for dyeing. A pH of 10 is more suitable for dyeing wool, while cellulose fibers do better with a higher pH of 11. The vat will eventually get to a pH 10 as the sugars create lactic acid in the fermentation but this could take a long time. I’ve had vats take weeks to reach pH 10.

photo by Robin Dreyer
Indigo!  – photo by Robin Dreyer

The addition of dissolved animal hide glue (a protein) to the vat will gently lower the pH by absorbing some of the excess lime. The glue will precipitate to the bottom of the vat along with unreduced indigo and sugars. Joy also suggested using natural gelatin (another protein) as an alternative to the glue but we did not have a chance to try this.

It’s very important to insure that the vat is fully reduced before adding anything that will lower the pH. I would wait at least a few days after making the vat before doing this.

I’ve had dyers tell me that the addition of the glue does indeed improve the hand of wool fibers. How much glue? I’m not sure. We started by using a recommendation by Michelle Whipplinger  in her Natural Dye Instruction Booklet. She suggests using the equivalent of approximately 1%  fiber weight. The glue needs to be dissolved in water.  That seemed a reasonable place to start. The key is to watch the pH and observe with both the eye and the hand.

13 thoughts on “Book is out! & Teaching at Penland

  1. And is the Japanese term “Nigawa” the equivalent to the animal “glue” which we find in traditional sumi ink production? Now being substituted with poly-somethings…..I have seen recently at a Sumi Company in Nara City Sumi for sale according to the variety of animal such as cow, goat, etc. and sold therefore at various prices. My supplier said that one reason they gave up production with the animal glue was that random people were bringing dead animals to their factory!!
    Greetings to Joy, too.

  2. received my book last week. It is full of useful information. a great addition to Catharine’s other book. Judy Anderson

  3. Congratulations Catharine! I received a copy last week and haven’t stopped playing with the concept of layering dyes. I’m cutting fabric right now…so much to learn. The book is fabulous…

  4. Thanks for the information about hide glue. While I use it, I assumed it was more like a hair conditioner and coated the fiber rather than reacting with the indigo and lowering the ph. For thio vats, I use this recipe of Michelle Whipplinger’s – When I have asked about this on other forums, the Europeans dyers said they were using gelatin; not hide
    glue. Congratulations on the publication of your book; look forward to seeing a copy.

  5. Thanks for the link to the indigo recipe. That’s more glue than called for in her handbook but the quantities of fiber are different. It might be more useful to base the amount on the volume of the vat. It only shows how we all need to experiment and learn what works.

  6. Congratulations Catharine, and thanks for sharing this useful information.
    I enjoyed reading this facts. I am also interested in manufacturing of organic and natural dyes.

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