Wednesday, August 25, 2010

A Change in Technique

Business has been good this summer, surprisingly, and so it has been difficult to take the time to blog, or to work on the project I am currently blogging about! Also, I have been invited by Rug Hooking Magazine to create a pattern for them to sell in the March 2011 issue, which is exciting to say the least! So work on that, to meet an October 1 deadline, is taking precedence at present.

I did want to briefly discuss a change in my dyeing technique, however. As we all know, there are many ways to get dye onto wool, and as many approaches as there are dyers. After reading many, many articles and books on dyeing, I settled, long ago, on adding the vinegar to the dye pot near the end. In theory, I thought this would cause the dye to take up more slowly, creating a more even effect on the wool, which is what I sell in my 'regular rug hooking' line of wool (as opposed to the mottled and otherwise figured colors that I'll begin offering in the future). I was having a terrible time getting an even effect on browns and greys in all values, and on many of the primitive formulas, all made using the three primaries. (I don't know if this is a problem when using preformulated colors, so I can't speak to that.) In particular, I had always noticed that the three colors laid themselves onto the wool in a particular order -- blues and reds first, and then the yellow last. The problem seemed to be that the first two would grab in places, and this would create undesirable blotches in various shades, once the yellow had bonded. This, despite nearly constant stirring. The situation was causing me to pull my hair out. I crave sending out wool with nary a dyelot difference, and some of my colors were all over the map with each batch.

One day, standing in the kitchen and pulling out the remainder of my hair, I had an epiphany. Why not actually follow the directions included with the dyes that I use? Those directions advise adding the acid to the dyebath in the beginning. It's actually a little embarrassing to admit that an otherwise intelligent person like myself would get so far into the process without doing this -- I had dyed hundred of yards of fabric by that time. Well, I felt that my colors couldn't get any worse, so I tried it, and lo! the three colors uniformly bonded with the wool in the pot!

I think the reason is that, because yellow has the least affinity for bonding with the wool (evidenced by the fact that it will tend to bond last), adding the acid in the beginning encourages it to bond more quickly, allowing it to 'compete' with the other two primaries, resulting in a more uniform distribution of the three dyes onto the wool. But this is just a guess. I'm no chemist.

I still have some issues with blotching, but not nearly as much, and faithful stirring minimizes this, as does adding the dye in 2-3 layers for darker colors. I pour 1/3 to 1/2 of the dye into the pot, stir it for several minutes (it feels like several hours) until I see that there is a nice base color, although there will still be plenty of dye in the water. Then, before the water gets too hot (which may also induce 'grabbing' on some colors) I add another 'layer' of dye and stir, and perhaps another. If the water is getting too hot, I add some cold water to the pot. For this reason, I start out with the smallest amount of water that will still allow me to produce an even color, leaving me room to add water. I like to avoid having more water in the pot than is needed, because I am always conscious of the amount of acid I use -- when dyeing as much as I do, cost becomes an issue. The more water in the pot, the more acid needed to bring it to the proper pH. (I also routinely re-use dyebath water that has been completely exhausted to conserve acid.) By the time I am done stirring, there is a nice even base layer, relatively dark, but there is still a lot of dye in the water. From that point, I just stir regularly until the dyebath exhausts. There may still be some darker areas in the finished piece, but I don't mind that, as long as those areas aren't reddish or greenish, but are simply darker values of the base color.

For the lighter values of my problem colors (up to a level 3 in my 'wool universe', or a 'light' value) I use a few sprinkles of salt, perhaps up to 1/2 tsp. in a gallon or so of water. Any more than that, or using salt when dyeing darker values will absolutely prevent all of the dye from being exhausted (especially yellow), which for me is anathema in my quest to provide a consistent result for my customers.

I have also experimented with the temperature of the water that I start with. I have read that some dyers add either the dye or the wool at the end, once the water is near boiling. I have not had success producing an even result this way, although in fairness I must admit that I haven't tried it when using vinegar in the beginning of the process. My results were very blotchy, and for some this may be fine, even desirable. To obtain an even color, I have found it best to start with lukewarm water in the dyebath. Cold water retards the uptake of the dye too much, because in the beginning I want to encourage the dye to bond relatively quickly, while I'm stirring after I've added the wool to the pot. Lukewarm water will encourage uptake, while still discouraging grabbing. With very light shades and my problem colors, I tend to make the water a little cooler, although not cold, just to slow the process down a bit further. With acid in the pot at the beginning, I am often able to exhaust the dyebath almost immediately for pale shades. As soon as it's exhausted I turn up the heat to get to the boil rapidly. In my business, freeing up a burner or a pot is essential! If I am dyeing several light values of the same color, I will often throw them all into one pot of acidified boiling water as they exhaust, freeing up both burner and pot. I call this pot a 'surrogate'.

I hope this will help some who may have questions, or who are just getting started. I have much more information about my dyeing methods in several articles I have written for Visit the link below to view them.

Articles on Wool Dyeing

And to see the results of my methods, represented in the inventory offered at my online store, visit:

Rug Hooking Wool

I welcome your comments.

1 comment:

  1. Well I must admit that I am like you; I add the acid towards the end for just the same reason! I am sure that's what a weaving teacher I had long ago told me to do. I do get colors that are not blended with the 3 primary mixes as well but I rather like that look for my hooking. I am starting to sell some dyed wool to a quilt store primarily for wool applique and have been concerned about the look for them. I will have to try this too. Funny; I was looking at the directions on the Pro Chem site the other day and thinking maybe I should try vinegar at the beginning too.... I haven't thought about the water temps though. Hmmmm. I will let you know how I do!