Wednesday, November 07, 2007

Fiber: Cherie Amour dye attempts #1 and #2

Here's what I'm starting with -- undyed wool, and Jacquard acid dyes in Emerald and Black. My goal is to achieve a soft sage green, something akin to the Leaf colorway here.

Acid dyes aren't really acid -- the acid in question is actually vinegar, which you add to the dye bath to set the color. However, they come in powder format, and you do need to be careful handling the powder, especially if you have, say, a history of landing in the hospital for breathing problems. Plus, it's hard to measure out powder like that, or to combine two different powders without getting them all over your kitchen. So the first thing I did was to CAREFULLY combine some powder with water to make a 1% dye solution (1 gram dye to 100 grams water). This is basically like a big jar of food coloring, easy to measure and mix with other colors.

The amount of dye you need is determined by the weight of the yarn you're dyeing, and this is where ugly math starts. You should use 2% to 4% of the fabric weight in dye -- if you're dyeing 100 grams of yarn, you should use 2 to 4 grams of dry powder. That's fine, but what if you're only dyeing two or three grams of yarn?

That's where the beauty of the 1% dye solution comes in. My first test batch was only about 2 grams of yarn, so 2% to 4% is 0.04g to 0.08g of dye powder. I don't have a kitchen scale that measures in those kinds of units, but if you remember, we've got our giant jars of liquid dye, and we can work backwards from there. I put in 1 gram of dye and 100 grams of water. So, if I want 0.04g of dye, I can just take 4 grams of dye solution (0.04 g * 100 g h2o / 1 g dye), and thanks to the magic of math, I have the correct amount of dye.

Batch A

I prepped the yarn for dyeing, and then stood around doing the math to get the right amount of dye. Since I wanted a relatively soft color, I decided to only use 2% of the fabric weight in dye, or 4 grams of my dye solution. The Emerald dye color is a fairly bright green, and to get the sage color I was after, I toned it down by using a 3:1 green:black ratio, 3 grams green solution and 1 gram black.

I prepped the dye bath as per the instructions, added my yarn, and put it on the stovetop to boil. I used a very tiny amount of vinegar to set the dye, based on the manufacturer's recommendations of 1/4 c vinegar per pound of fabric. The math on that is painful, and I eventually wound up putting the vinegar in solution as well, to get a total vinegar amount of 0.25g (basically, a few drops -- a quarter of a 1/4 tsp).

The result is the bottom yarn. It's definitely soft -- too soft, in fact, and with not quite enough green in it. It's a nice celery color, but I don't want a whole sweater in that color. So, back to the drawing board.

Batch B

This time, I cut off 5g of yarn, to make my math a little nicer. To deepen the color, I decided to step up to using 3% of the yarn weight, 0.15g dry powder, 15g of my dye solution. I changed the green-to-black ratio to 4:1 green:black, or 12g green solution and 3g black solution, so that it would be more green and not as gray. I also decided to just pour in a glug of vinegar, thinking that perhaps I didn't have enough vinegar in the previous batch to help the dye penetrate the fiber.

As you can see from the photo above, those things made a BIG difference. Batch B is much, much more saturated, and the green is deeper. I think it's mostly due to the extra vinegar -- even the first batch had a lot of dye in it, more than enough to really darken the yarn.

I think that this color is very nice indeed. It's darker than what I'd intended, but it would be quite flattering to me. You can't see it in the photo, but there are subtle variations in the color, and it gives the yarn a lot of depth. I'm going to turn it into a small swatch to see how I like it knitted up.

I am debating whether to make a third batch and see if I can hit on the sage green I originally wanted, to compare it with the olive Batch B. I'm thinking of using 2% of the yarn weight in dye again, and adding about a teaspoon of vinegar, rather than the coupla-tablespoons from Batch B.

I'm still a little nervous about dyeing the whole pile o' yarn, but these two test batches are encouraging.

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