Sophie: I’d recommend you read this article: http://www.knitty.com/issuespring07/FEATdyeyourown.html it has lots of useful info. I am planning to write a post on my blog at some point detailing exactly how i dye my yarn, but that’ll take a while cos i want to do step by step pictures. The knitty article is pretty much how i do it though, execpt i add salt when dying blues (and green/purple because they have a blue component) because without it the colour seems to be very weak...reds and yellows don’t seem to need the extra salt.
For your first attempt i’d suggest using a skein much shorter than the one in the knitty article, just because its easier to work with a smaller length. And don’t forget to treat your wool gently so it doesnt felt.
Oh, and it may seem obvious, but remember to use wool or other animal fibres, or nylon, this process doesnt work on plant fibres or other synthetics.
Suse: no, the colour does not run. I can’t remember the chemistry behind it, but the combination of the acid and the heat makes the dye bond with the wool in such a way that its relatively colour fast. For example, the sock in the picture I posted has probably been washed in a quick 40 degree machine wash about ten times, and has only faded slightly. Ideally you’d want to handwash your stuff and keep it away from strong light, but i’m just too lazy to handwash socks...i figure if the colour fades, i can always dye them again.
