Today was the day I planned to publish the pattern for my first set of mittens, keeping with the concept of "Mittens Monday". And... This isn't it. Yeah, sorry to those of you who are waiting for it; it needs some... Let's call it splitting up. Well, this is still about mittens! What was one pattern with some notes for adjustments will now get separated into two different patterns. It's not complicated; I just have to take the time to decipher my chicken scratches of notes everywhere.
I had originally thought the two different yarns I was using were the same brand, but I soon realized that they weren't. That didn't stop me! I made gauge swatches and they matched, so I kept working. What a big surprise when I finished two pairs of mittens in two sizes to realize: They're almost the same size! Oh no, what do I do?
So, I could complain. I could cuss, kick, and throw my notebook down in disgust. But what I will do is... Okay, who am I kidding? I already did all that; I'll just spare you the complaining and give you a lesson/warning. Sound good?
Alright, let's go over how I was making the pattern: Same pattern, two sizes, and two different yarns, but with matching gauge swatches. I had already planned on an additional round for the larger size to increase the length, as well adding to the length of the thumb. Now, we'll skip ahead to the results: One mitten would obviously be longer, but when I tried them on, they didn't differ in circumference!
And on to the explanation of this mystery, minus all the math mumbo-jumbo: The yarns are sized close enough to work up the same in a gauge swatch when counted by inches - more specifically, a gauge swatch that was worked flat in rows. By sight, one yarn simply appears "fluffier". I'll throw some guesswork in there and say that maybe - and this is just a guess - I think my tension could vary a bit between the yarns, too. One has a smoother texture that doesn't catch, so I'm more likely to work my stitches with tighter tension. Due to the anticipation of the second yarn splitting, by instinct I work with it more gently.
But back to that not-really-math, solid reason: Inches are bigger than centimeters. (Duh...) When good ole Americanized me counts my stitches in inches, I'm not getting as close of a measurement as I could be. Sometimes, you have to stop being the sixth-grader that's groaning why do I have to learn more measurements when I already know feet and inches?; and you have to flip that ruler over to get a better gauge. (And get a flat ruler, too. Those tape measures can throw off your measurements.)
Now why should that matter, when four inches equals ten centimeters, and I still have the same number of stitches in both swatches? That's a bit of a phenomenon... When counting the number of stitches together, you get the same count. But if you use those centimeters to measure each stitch individually, one is just a tiny little line wider. It doesn't add enough to a four-inch gauge swatch to make much of a difference by sight, but it's enough to change the finished pattern.
Now, let's add some more technical stuff: Thickness. Because I worked those gauge swatches in rows, the thickness of the yarn didn't make a difference. So, let's see a show of hands... Anybody have a guess where I went wrong? Yes, yes, you in the back, screaming "you're working a pattern in the round, dummy, you need to work a swatch in the round too!"... Yes, you're correct. I'm the dummy that worked a flat swatch for a round pattern. I was trying to save time. I was cheating. I was too lazy to work more stitches up in the round. And it made a big difference.
The dummies' explanation of why that changes the size: In small swatches, the flat pattern will just fluff upward, and you think "ooo, fluffy". But if it fluffs out more, then it fluffs inward more, too. When you're making a pattern for something like a hat, or sweater, or you know, mittens... Well, something has to fit inside that pattern. The thickness of the yarn decreases the inside of the hole.
So I get to translate what all my little marks, numbers and symbols mean in my notebook, and there will be two patterns, even though they're almost the same. They're not the same enough to make sense of all the variations for the two different yarns, and it could get hard to understand. It just has to be two separate patterns, and I wish I had realized that before I went scribbling notes that just confused me in the end. Do you always need to wok a gauge swatch in the round for an in-the-round pattern? Maybe-probably-not if you know the yarn you're using is the same as called for. But if you're using a substitute, and especially if the texture varies, then it's probably a good idea to give it that little extra test.