Saturday, February 27, 2010

The theory of dyeing

Now, the fun part. Dyeing the wool!

I managed to find some Kool-Aid, in three colours: orange, cherry and grape. I also bought neon food colouring.

Let's recapitulate. To dye wool or other protein-based fibers, you want an acid dye. Most (if not all) dyes used in the food industry are acid dyes, so jell-o and regular food colouring also work. Acid dyes work on protein-based fibers, that is, hair or even skin, which means you can dye wool, mohair, alpaca, human hair, and all other hair you can think of, but also silk (worm spit), finger nails, skin (leather), and bone. As an added bonus, it also dyes nylon. It's extremely fugitive on plant-based fibers such as linen or cotton, and doesn't work at all on sythetic fibers, wich is why I tie my hanks with leftover bits of acrylic yarn before dyeing.

You need two things for the dye to work. An acid, and heat. The acid in kool-aid is citric acid, and usually you don't need to add any more. With other food dyes, you add white vinegar. You could do the same with lemon juice or stronger acids, but white vinegar is dirt cheap. For heat, you can work on the stove, or, to make things simpler, you can do the same I do and use your slow cooker on the Hi setting. Many people will seal their wool in a zip-lock bag and heat it slowly in the microwave to set the dye (careful not to scorch your wool! it has to remain wet at all times). The usual technique is to heat 2 minutes, let cool a bit, then heat 2 minutes, then... you get the idea.

There is one thing you must be careful with, though: wool felts. Two things will felt it: agitation and sudden temperature changes. Which means that you can heat it thoroughly, as long as you don't suddenly dump cold water on it. It also means that it's important to manipulate it as little as possible, especially when it's hot and wet. With the slow cooker, I start my wool in lukewarm water and let it heat gradually, which is what a slow cooker is meant to do anyway. I add the dye at any point during the heating process. It doesn't matter much if it's not hot enough yet when I add the dye, it only means that the wool won't absorb it all before it reaches the "magic" temperature so the colours will mix a little more in the dye bath. If I were to wait until it was very hot, then the wool would absorb the dye faster before it had a chance to spread and I'd get more variation in the colours. It's not better or worse, it's simply a different effect.

This post is getting long, so I think I'll show you the pics in the next one!


  1. I have to tell you... some of those pics look like badly abused brains. *grin*

    but the colours are fabulous. I had no idea you could do that with koolaid. We must talk about this striped silk/cotton blend I have...... :-)

  2. And this was on grey wool. I can't wait to try that on white!

    Do you know how much silk to cotton your fabric has?