Tuesday, May 22, 2012

Scenes from a Dye Class: Madder and Cochineal

Linen scarf, ombre-dyed with madder and cochineal

Today at the Weaving and Fiber Arts Center in East Rochester, NY, four fiber enthusiasts and I spent several hours playing with madder and cochineal, seeing what reds we could achieve with these two ancient dyes.

We had some surprising results! Using cochineal bugs purchased online from Wild Colours in the United Kingdom -- and following their directions -- our fibers came out in vivid purples and lavenders! I bought a 100 gram bag of bugs (sounds nice, doesn't it?), ground them up in my coffee grinder, doused them with boiling water and soaked them overnight, strained them in the morning, and divided up the dye solution between two dye pots. So I used about 50 grams of ground cochineal for maybe 300 to 400 grams of fiber. Here are some results.

Wool yarn on left, cotton on right

In my experience, cochineal produces magenta, rose, and salmon-red colors. How did this happen? Our water is hard -- perhaps that changed the chemistry. I used a high concentration of dye powder, which might have had some effect. Does anyone out there know how we got purple from cochineal, using nothing but alum mordant?

More results below, from both cochineal and madder, with an alum mordant. By the way, I had to increase the intensity of the madder dye, because our results at 10% WOG were lackadaisical. I upped it to 20% WOG (that's dyeing jargon for a ratio of 20 to 100, weight of dye to weight of fiber).

Wool roving dyed in madder, alum mordant

Skeins on drying rack: madder on left, cochineal on right

Different fibers, same vat, different results: Tencel on left, silk on right

Many thanks to Barbara Clements, Eleanor Hartquist, Joyce Leary, and Gretchen Wheelock for a wonderful afternoon!


Andrea said...

I am curious what kind of pot you used when you got the purple color. Sometimes the metal in the pot can react with the dye just like the alum does, such as copper or iron.

Denise Bolger Kovnat said...

Andrea, you know, this remains a mystery to me. I used a stainless steel pot. And the heck of it is, I REALLY LOVED that purple color. It was consistent on all the fibers we were dyeing, also. I would welcome any other suggestions!

Anonymous said...

When you have extracted and strained
any dye, put few tablespoons in a clear
glass and hold up to light. See if
it's what you want. Add ammonia a
few drops at a time to the dye solution in the glass to "blue" the solution,
add few drops of white vinegar to
the solution to push it to "redden" it.

It's about the ph. Hard to say what
created the deviation from expected
norm, but most likely your water supply.Best way to have more control
is to use distilled water, but for
large scale dyeing, not always practical to buy that much water.

Hence, the help of ammonia/vinegar.