What to use when - how to substitute yarns in your knitting projects

In book club last week, we had a super interesting discussion about Klara and the Sun.  Klara’s an Artificial Friend, an AF, an advanced robot doll whose purpose is to pal around with Josie, a thirteen-year-old girl.  Josie’s very ill, and her mother is so worried about losing her, that she investigates the concept of replacing her daughter with an AF designed to look just like Josie.  But looking alike isn’t really enough, is it?  It’s about their personality. What makes them laugh or cry?  How do they respond in different situations?   Klara, we find, is a storehouse of just such information about Josie, and Klara’s database can be downloaded to create a nearly perfect replica of not just Josie’s appearance, but of her essence

While not nearly so futuristic, the process is rather like substituting yarns.  How many times have we fallen in love with a pattern only to find out that the yarn’s been discontinued, is out of our price range, or is otherwise unavailable.  Desperate to create this garment despite our access to the specific yarn, we begin to search for a satisfactory substitute. 

What does this quest look like?  Where does it begin?  Isn’t it just about finding the same gauge yarn and buying the right amount?  No, of course not. Just as with people, there are a million tiny factors that go into creating a given yarn’s personality.  Certainly the right gauge is a good place to start, but there are lots of other factors to consider as well.  What is it about the yarn that made the designer choose this yarn and not another? What is the main characteristic the designer wanted from this yarn?  In other words,  what is the ideal yarn’s essence? 

I usually start with Ravelry and look up the yarn used. What am I looking for?  Well, basically, I am looking to see what is this yarn’s primary characteristic. What is the feature that you notice first about it?  What makes this yarn work in this design better than a host of other options? I usually start with the following.  

1. Texture - What is the texture of the yarn used in the pattern?  Is it smooth or fuzzy?  Is it a consistent texture along its length, or does it go from thick to thin in places? Are there nubby bits in the yarn? Texture matters because the greater the texture of the yarn, the less stitch definition there is.  If you want to highlight the garment’s stitchwork, chances are good that you’re looking for a smooth yarn with good stitch definition.  If the garment you want to recreate has a soft fuzzy kind of halo to it, you’ll need something with a bit of a brushed texture.  Texture also plays into weight, as does construction, below.  
2. Fiber content - If the garment you’re making is designed in a cotton/rayon blend, substituting wool would give you a different kind of fabric.  Rayon lends suppleness and gives your fabric drape that you might not get from a wool of the same gauge.  Same thing generally about substituting cotton and wool for each other.  It’s not wrong, it's just that the result might be different from what you expected and were hoping for.  
3. Construction - Back in the day, construction referred only to a yarn being woolen or worsted spun, how many plies were in the yarn and how tightly those plies were twisted. Now, we have so many different fiber construction methods - chainette, blown, tube.  If the designer used one of these modern yarns, they are likely looking for a light weight, and possibly greater elasticity. 
    

There’s no particular order for examining these characteristics.  In fact, they are all interrelated and influence one another.  For instance, construction influences texture and weight.  Fiber content influences construction and weight, and so forth. 

I'm thinking about this especially as I look at new Tweed Haze, from Rowan. There's a whole book of designs for it, but I wondered what else would it be perfect for?  Why Brushed Fleece, of course.  Same gauge, yes, but more importantly, it has the same personality - light, lofty, fluffy, but maybe a little more playful. It could easily substitute for Brushed Fleece in everyone's favorite free pattern, Sucre. 

At the end of the day, you get to choose. Get just one ball of different yarns and make lots of swatches--see what you think about each one. That yarn and that time is never wasted, because you’re learning as you go. 

I look forward to seeing you and your swatches, and helping you figure out the essence of the yarn you're seeking.  You are always welcome here.

~Ellen