Saturday, August 20, 2011
Capturing the Sun, Round One
I have been fascinated lately with natural dyeing. It is a reasonable outgrowth of my other fiberish and gardenish pursuits. I am an inaugural member of the first natural dyestuff CSA, and am on the edge of my seat awaiting the first magic box. Meanwhile I have been reading up and gathering some potential dye plants from my own environment. So far I have collected from my garden: Coreopsis flowers and seed heads, Lingularia flowers, Arborvitae seed pods, and Mahonia berries. All of these have been labeled and put into the deep freeze. Along with them went several pounds of slightly-rancid bing cherries. (Yes, Laura, I do know that cherry pigments are fugitive, but I have an experiment in mind.) I have also set up 2 one-gallon jars of iron-water starter. Sort of like sourdough starter, feeding small rusty objects into vinegar-laced water will provide an unending supply of iron-rich mordant. I created 2 jars, because one of the jars contains rusty baling wire which, if it was galvanized, will also contain zinc. Different trace metals can greatly affect dye results. The other jar contains iron railroad spikes collected about 25 years ago along the former route of the historic Atlantic Coast Lines in Wilmington, N.C.
With some exceptions (most notably indigo) dyeing with plants is a 2-step process. Plant pigments don't really want to stick to fibers unless they have an intermediary, known as a mordant. The most common mordants are metal salts and are REALLY poisonous. Alum is one of the least poisonous (small amounts are food-safe) and brightens colors without modifying them, so it is the home dyer's mordant of choice. Iron is also commonly used, but it darkens or "saddens" the color. Using an aluminum or iron pot can be a substitute but may not provide the trace metal in high enough concentration. Everyone with me so far?
For my first experiment I divided 10oz of handspun Blue Face Leicester superwash wool yarn into 3 batches and simmered each batch in a separate solution: alum, RR spike iron water, and baling wire iron water. Note: be careful not to boil the iron water if you don't want your kitchen to smell like a machine shop. After copious rinsing, the alum skeins looked just like they had started and the iron skeins were a dark tan.
Mordanting is a bit like writing with invisible ink: the magic is revealed after the second step. I just couldn't wait until the weekend. Dreaming of sunny yellow socks to brighten up the depths of winter, I filled up the dye pot with water and tossed in the 12oz of Coreopsis flowers from my garden. The water started turning yellow almost immediately. I simmered the flowers for an hour. Along the way I tested the temp, and since it was too low, I turned it up, and gave it an extra 30 minutes. Then I poured the whole thing through a pillowcase to filter out the solids and returned the sunny yellow liquid to the dyepot. I added all the (presoaked) fiber and simmered for about an hour.
Each time I peeked, it became more evident where I went wrong. I should have dyed the alum-mordanted and iron-mordanted yarn seperately. Despite all the rinsing I had done, enough iron was floating loose to sadden the color of the alum-mordanted yarn. Still, I expected to get gold. In the pot all the yarn looked a uniform brownish color. It was not until I removed it from the dyepot that I could see the final two shades of deep bronzey green. I own eight books on natural dyeing, and none of them would lead me to expect this color of green with Coreopsis mordanted with alum and iron. That is the magic of natural dyeing! (For those technically inclined, the pH was lowish, 4.5, and I was dyeing with tap water in a stainless steel pot. Wonder what's in my tapwater...)
There was still plenty of color in the dye bath, but I didn't have anything else pre-mordanted, so I tossed in a half cup of alum and some white BFL and light grey Shetland roving. Those came out much closer to expected, but on the light side.
So this winter I will have the sunny green socks of summer.