It’s time to collect black walnuts! The black walnut tree (Juglans nigra) is native to eastern North America. The outer husk of the nut is the source of dye. The colorant is juglone. It is a direct dye, which means that no mordant is necessary when used with a protein fiber. There are some tannins in the husk but that is very secondary to the strong juglone. I have not found a better dye to achieve a rich, fast, brown on protein fibers. Cellulose may be dyed as well, but that requires a mordant.
The best time to gather the nuts is when they are still green: newly fallen or ready to fall off the tree. If the nuts rot and turn black on the ground the dye will be damaged. I preserve the fresh nuts in the freezer for year round dyeing.
I have experimented with drying the nuts carefully on racks to prevent rotting. When I compared these dried nuts to fresh/frozen walnuts in the dyebath it was clear that they contain far less dye. On the other hand, drying may be a practical solution.
I have learned that the secret to dyeing with black walnut is slow dyeing and lots of patience. I put the entire nut(s) in a mesh bag (fresh or dry), cover with water and simmer until the outer skin (the exocarp) breaks open, releasing the soft husk underneath which contains the dye. Then I cool the bath a bit, add the fiber, leaving the entire nut in the bath (in the mesh bag) during the entire dyeing process. The mesh keeps the fiber clean. I heat the dyebath slowly and leave it for a long time. There were many occasions that I was disappointed in walnut dye, only to finally learn that it takes TIME. I still have to resist the temptation to add more walnut to the bath during the first hour of dyeing, remembering that the dye will get darker with a longer bath.
My typical approach to dyeing with walnuts is to grab a handful of them, making a good “guess” as to how many I need. I decided to approach the dyeing more scientifically in order to control the color and know how many walnuts were actually required to obtain the color I wanted.
A fresh walnut weighs about 90 grams. A dry walnut weighs about 30 grams. The dry nut contains a lot less water and now I know that it also contains a lot less dye.
- The nut inside the husk (this is the not the dye) = approx. 20 g
- A fresh nut contains approx. 70 g of walnut dye material
- A dry nut contains approx. 10 g of walnut dye material.
I now calculate about one fresh/frozen nut per 20 grams of fiber (or about 350% w.o.f.). If I am using dry walnuts I will double that amount, at least. Many more dry walnuts will be required to achieve the same color as the fresh walnuts.
Black walnuts are a most versatile dye. The presence of tannin means that the color can be dulled and deepened with an afterbath of ferrous but when dyed over a deep indigo, a near black color can be achieved on wool or silk without the use of any mordant.
Catharine’s new edition of Woven Shibori, focused on natural dye, is available from local booksellers or Amazon.com