Choosing 2 Ply vs 3 Ply Yarn for a Knitting Project

I've had a couple of people ask me to go into more detail about why I would pick a three-ply yarn instead of a two-ply yarn for Rogue if I were to do it again. So, since I am without an exciting knitting progress picture for the post, and I think it's something that I never would have thought about if I hadn't taken up spinning, I thought I'd revisit this topic.

The best thing I can do to start the discussion is to point you to a post I made in April, wherein I discuss the geometry of two and three ply yarns. I'd recommend clicking on it and taking a look, at least at the pictures, because it's something of a long discussion, and I'm far to lazy to repeat it tonight. And I'm going to assume, going forward, that you understand the geometry of 2 and 3 ply yarns.

OK, so now you know that 2-ply yarns are two dimensional and 3-ply yarns ar three dimensional. So how does that factor into deciding what kinds of yarn to use for certain kinds of knitting projects? Well, let's take Rogue. Rogue has a bunch of lovely cabling in it. Cabling is a three dimensional knitting technique. The idea is to create a raised area of stitches that you can look at from multiple angles and see a defined, rounded, shaped structure. When you choose a three dimensional yarn to work with a three-dimensional structure, you end up emphasizing that texture and rounding it out. It brings the texture work to life better. Three-ply yarns have a rounder quality to them as well, and that also helps to pop out that cable.

So does that mean that 2-ply yarns are inappropriate for cabling? Not at all. 2-ply yarns can still be excellent for cables and designs. But they give you a different look. For instance, do you remember my Pearl Buck Swing Jacket? I made Pearl out of Silky Wool which is a two ply yarn. The textured stitches lay flatter against the fabric, creating a more subtle patterning. Now take a look at Sigil, a cardigan I made with a bulky weight 3-ply yarn. See how those cables jump right out at you? That has a lot to do with the extra dimensionality of the three-ply yarn.

Two-ply yarns, on the other hand, are wonderful for lace work. Lace is meant to lie flat. With lace, you're not interested in a 3-dimensional fabric, you're interested in being able to have beautiful stitch definition that will lay flat and show off all the open work, making 2-ply yarn a perfect selection for lace-based projects. Compare this short scarf knit in a two ply yarn that I spun with my Flower Basket Shawl which I knit out of a 3-ply handspun. Notice how the two ply scarf shows off the pattern better than the three-ply shawl? The extra-dimensionality of the yarn in the shawl obscures a bit of the pattern work in the shawl. It's still a shawl that makes me perfectly happy (and keeps me a bit warmer), but it's a different look than if I'd chosen a two-ply yarn.

Of course, it is not solely the number of plys that determine the final look of cables and lace in your project. You still have to consider the loft of the yarn that results from the fiber the yarn was spun from. For instance, wools from Merino, Targhee, Cormo and CVM sheep are all springier and crimpier and pack a lot of poof into a yarn. That's one of the reasons why two-ply 100% merino Koigu PPM has the three-dimensional look of a 3-ply yarn. Yarns from sheep like the Blue Faced Leicester tend to have less springiness and the yarn looks a bit flatter. Spinnning technique makes a big difference too, if you spin woolen, you get a loftier yarn than if you spin worsted. And then you have to factor in gauge. Knitting a poofy yarn on smaller needles yields a different fabric than if it is knit on big needles. For instance, I probably would have gotten better resolution on my Flower Basket Shawl if I'd gone up a needle size or two.

This is why I say that if I were to buy yarn for another Rogue I'd probably try to start with a three ply, but I'm happy with the Bartlett. The Bartlett has a reasonable amount of dimensionality that comes in from the wool that it's made of, and the way the singles that make up the two plys in the yarn are spun. To my eye, it looks like the singles were spun semi-woolen (or semi-worsted, depending on your perspective) so they have some extra loft to bring to the party once plied. So while I don't expect the cables to pop quite like they did for Sigil, knit at the gauge that I'm going to knit it in, I should still get nice resolution and dimensionality with the cabling in Rogue. My Rogue will be a little reserved, but those cables will still show up well and let people know they're there. Which seems about right for a sweater that gets it's name from a stealthy sort of character.*

*At least if you're playing a Rogue a la D&D -- which I have on my brain right now, since I've been digging into the last two major add-on for Neverwinter Nights before I charge into Neverwinter Nights 2... yes, I am a geek on so very many levels!