Recently attended a dye day at Kathleen McCormick's house. Kathleens weaves beautiful atmospheric baskets from her own brown willow and lovely rugs on her loom, often using her own hand-spun and hand dyed yarn. (www.wovenbykathleen.ie). The main objective of the day was to use different pro and post-mordants along with various natural dyes and see the modifying effects.
We had thought of using iron and a post-mordant to "sadden" the colors but omitted this as there were so many pots bubbeling away that there was no space left - any anyway, the colors we got were muted enough. Natural dyes tend to be gentler , more muted colors I think although the yellow I got last year from Buddlea was surprisingly bright and might have done well with some iron post-mordant.
I was delighted to see the effect of copper sulfate on onion skins and Woundwort (Stachys). Máire Ní Neachtain brought lots of onions skins and they made a lovely golden yellow on alum pro-mordented wool. Then the addition of copper sulfate yielded a nice light brown. Kathleen had harvested lots of Woundworth from hedgerows and waste grounds, boiled it, strained it and then added un-mordanted wool to the pot. Un-mordanted - yes!. After that, added copper sulfate yielded a soft, organis green. I really like this one too.
Rothholtz, a red bark dye, gave a unexpected deep maroon on my white alum-mordanted wool though more of a lighter red on others. I think mine had more alum attached as I had steeped it in alum before bringing it along as well as in the communal alum pot at the house.
Pre-mordanting with rhubarb did a good job too. This was perhaps my favorite new piece of information as I grow rhubarb and usually the hens get the leaves (apparently they don't suffer from the oxalic acid within) - but they get bored with them as there is so much to choose from at this time of year. They're not getting any next year!
Here are my little samples;
There was a blue dye too - which worked well on other people's yarn - giving a deep inky blue. I had Kathleen's specimen but it washed out, not sure why.