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.
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.
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.
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.