Natural Dye Notebook :: No 27, Sumac

Posted by Erin Howe on

I’d heard the name sumac mentioned again and again as I began my dye research, so I was happy to get my hands on some sumac and see what the buzz was about. 

Not having any idea of what to expect, I had to say the results were pretty disappointing:

Grays and browns from the berries was the best I seemed to be able to get. A dud, I thought. 

But then I was in the library in Asheville, waiting while my son attended film camp, and I picked up A Weaver’s Garden by Rita Buchanan. She had this to say about sumac:

“In contrast with the vivid reds of the leaves and berries in fall, sumac gives disappointingly dull colors on wool–shades of tan, beige and gray with different mordants. Whatever red pigments sumac has aren’t concentrated or stable enough to serve well as dyes. But sumac is valuable to dyers for another reason. The leaves, twigs, and berries contain tannins: dried leaves have concentrations as high as ten to twenty-five percent. Some dyers add a handful of sumac leaves to dyebaths of other plants to improve the fastness of the color when dyeing wool. Sumac tannins are especially useful as mordants in the alum/tannic-acid/alum sequence outlined for cotton, flax, and other plant fibers. In the summer, use a pound of fresh leaves to make tannic acid solution for a pound of fibers, in the winter, use just eight ounces of dried leaves.”  

As soon as I got home, I took a sumac-dyed cotton swatch and tested it with my iron dip. 

And it turned very dark gray. 

Aha. So maybe sumac isn’t a great dye by itself, but maybe it could serve as a more or less colorless tannin mordant? I looked up the alum/tannin/alum process Rita referenced and squirreled it away in my memory. 

That weekend I tried it with a crockpot and a cotton/linen blend fabric, but instead of coming out with a blank mordanted fabric, I came up with a light brown:

So I’m confused by what went on there, and this will require further experimentation. But as this is a notebook, I can come back and update when I’ve done that experimentation. I’m just glad that sumac isn’t the dud I thought, and isn’t off the table.

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