Silk satin ribbon dyed with cochineal, alum mordant
Using the book Colours from Nature: A Dyer's Handbook by Jenny Dean, I dyed some fabrics with cochineal, using an alum mordant. I started with the bugs themselves and ground them up in a Krups coffee grinder. (No mortar and pestle for me -- it takes too long!) Silk takes dyes brilliantly, I've found, so it's my fabric of choice. Instant and immense gratification. The ribbon you see above was soaked for maybe two days in an alum mordant solution.
Silk gauze dyed with cochineal, alum mordant
This silk gauze (above) was dyed using the same recipe. Because the fabric is so light and airy, it doesn't have the brilliant fuschia/red that you see with the silk ribbon. Still, this delicate pink is quite lovely!
Wool locks dyed with cochineal, alum mordant
I threw these wool locks in at the last minute -- mordanted in alum for maybe 1/2 hour, no scouring, simply dyed "in the grease." Perhaps I'm seeing the results through rose-colored glasses ;) but I think they're beautiful. I'll use them in spinning, combing them out a bit with a Dutch comb and then throwing them randomly into my handspun when I'm plying. It adds a lot of interest, texture, and color, creating the hand-spinner's version of a novelty yarn.
Locks dyed with cochineal, the second sample using an iron after-mordant
I've read a bit about using various "after-mordants" such as iron or copper. Copper tends to brighten the colors, while iron will "sadden" or tone down a color. Just what is an after-mordant? It's exactly what it sounds like: After you have dyed your fiber, you place it in a bath of iron or copper or whatever you choose to alter the color after dyeing.
And how do you create the iron bath? I used a fistful of rusty old nails and whatnot -- actually, some of them dug up by my dad as he searched the bed of the original Erie Canal. I placed them in a bucket of water, added one cup of white vinegar, and let the solution sit for about two weeks. Now I have my iron after-mordant, to be used whenever I want to "sadden" a color.
Next I have some goldenrod I gathered from a late-summer walk. I'll keep you posted on the results!