Double Knitting. Like how airplanes fly, or the appeal of Sean Hannity, it's one of life's mysteries. Lucky for us, we don't have to know why it works, we only have to know how it works. And Uncle Stashley definitely knows how it works, and in his first 100% fully useful post, he's going to spill the tea*.
In case you're not sure what double knitting is, it's basically a method of creating two fabrics at the same time. The advantage to this is you can do fun stuff with colour changes, and create basically reversible mirror-image scarves, hats, etc., that are super-squishy and warm. If you get good at it, you can go even more complicated, but as a wise woman once said (in my last musical: Climb Every Beanstalk) "It's quite complicated enough!"
So here's how it works. Take a yarn, any yarn. Use circular needles, any sufficient size, it doesn't matter what length. If you're comfortable with double-pointed, also good--we need to be able to knit from both directions.
[Note for die-hard straight needle enthusiasts: You can use straight, but you will have to transfer all your stitches onto another needle after half of the rows, in order to get them facing the opposite direction. Let me know when you've finished your project, and I will come visit you in the Sanatorium for Distressed Knitters with a bouquet of hyacinths.]
Oh, and don't get daunted. This is actually easy stuff. Once you understand it, you can do it without thinking much (like how, by now, you likely are able to make ribbing by simply knitting where you see knit stitches and purling where you see purl stitches and you don't have to count the pattern out any more).
Step 1. Cast on your required number of stitches. If you want finished fabric that's 20 stitches wide, cast on 40 stitches (that's 20 pairs).
For our example, let's keep it simple. There are 3 pairs of kids in the Brady family, so we'll cast on 6 stitches, and we'll end up (one day, trust me) with a tiny length of fabric only three stitches wide once we're done:
Well done! Let's name them, so we can keep our pairs straight. From right to left (I think I'm turning Japanese) we have two older kids, two middle children, and the two youngest Bradys:
Step 2. Knit the Brady boys, and slip the Brady girls--slip as if to purl. We'll be dealing with the Brady girls later in a different colour.
[Note for those who like to understand the overall concept: in Double Knitting, for every pair, you're going to slip one of them, and make a new stitch into the other (sometimes, knit, sometimes purl, more on that later). If you are KNITting stitches, then you slip their counterpart as if to PURL (i.e. with yarn in front), but if you are PURLing stitches, then you slip their counterpart as if to KNIT (i.e. with yarn in back).]
After knitting the boys and slipping the girls, you'll get this:
Those Brady girls look pretty stretched out, but don't worry, we're going to deal with them next, and they'll relax back to normal.
Step 3. DON'T TURN YOUR WORK! Merely SLIDE your stitches back to the other side (that's why we needed circulars or double-points). Grab some yarn in a contrasting colour (we'll use pink for our demonstration). And now we're going to slip the Brady boys, and we'll purl the Brady girls.
[Note for those who like to understand the overall concept: anything you knit (or slip knitwise) is going to come forward to your front facing fabric, anything you purl is going to recede to the fabric layer behind. Of course, once you turn it around, the layer behind will show its outward-facing stockinette* side. Nice!]
After slipping the boys and purling the girls, you get this:
And you'll notice that the girls aren't stretched out any more.
Step 4: TURN your work (at last!), and notice that you have two working yarns happening. Best practice is to use the one you just finished with (in this case, the pink), but before you plunge in to the main action, you want to "lock in" your temporarily-unused yarn, so carefully lift your blue ball of yarn up toward you and around the pink strand, then start knitting with the pink. That wasn't so hard! (But a failure to wrap the pink yarn with the blue yarn will cause you to have holes on your edges. Nobody wants edge holes).
You will now be knitting the Brady girls, and slipping the Brady boys as if to purl (with yarn in front)--essentially what you did a few steps ago, only because we're looking at the other side of the fabrics now, who gets slipped and who gets knitted are reversed:
And once you complete that row, it looks like this, with the Brady boys outstretched:
Step 5: SLIDE the work over again, and pick up the blue yarn. This time slip the girls (as if to knit) and purl the boys:
And you should end up here:
Except, because of the magic of double-knitting, the stitches that are knitted will come forward, and those that are purled fall back, so when you turn it to start the next round, it looks more like this, really:
The current "live" stitches will show up in both colours, but your fabric will really only look like whatever colour was knitted on that side (or purled from behind).
You will ALWAYS knit four lengths, at least until you bind off:
Knit Colour 1, Slip Colour 2 wyif.
SLIDE. Slip Colour 1 wyib, Purl Colour 2.
TURN. Knit Colour 2, Slip Colour 1 wyif.
SLIDE. Slip Colour 2 wyib, Purl Colour 1.
Danger, Will Robinson: if you lose track, don't panic. Are both your working yarns on the same side? Then it doesn't really matter which one you pick up (i.e. whether you start at 1. or 3. doesn't make a difference). Are your yarns on opposite sides? NOW it matters, because if you pick up the wrong yarn, you're going to keep slipping and stretching the other colour to its limit! So count the rows. If you have 11 rows of Colour 1 and only 10 of Colour 2, it's time to work with Colour 2!
Double Knitting: Making a Pattern.
It could be your initials, or a circle, or a flower, or even a single stitch. Let's do a single stitch, just to illustrated. If you like, you can pretend it's the Brady's housekeeper Alice, popping her head up in the middle.
Simply knit, slip, as normal, until you get to the spot where you want to mix it up a bit. In our case, we want the Peter/Jan column to be the opposite colour that it normally would be.
Unlike Fair Isle or intarsia, you can't just pick up the correct colour once you get to the stitch. Your pink yarn is still sitting over to the right, waiting to be worked. So what you do is you suddenly switch from Knitting the boys, slipping the girls (wyif), and instead you PURL Peter, and slip Jan as if to KNIT (wyib):
Then, you guessed it, SLIDE your work back, grab the pink, and slip (wyib) Greg, purl Marcia, slip (wyif) Peter, knit Jan (that's our ultimate pink-in-the-front stitch, right there!), slip (wyib) Bobby, purl Cindy. TURN. Still with the pink, now Knit, slip(wyif), Purl, slip(wyib), Knit, slip (wyif), excellent, SLIDE, get the blue, and slip (wyib), Purl, slip (wyif), Knit (that'll be a blue stitch dramatically popping its head in), slip (wyib), Purl. Tada!
[Note for those who like to understand the overall concept: whichever colour you're currently working, whenever you get the bit that wants to be in a contrasting colour, just switch gears and give your pair the opposite treatment. This ensures that the contrasting colour, for that side of the fabric, will come forward for a change. Nifty!]
I sometimes over-explain, so if by chance I've under-explained, let me know, and I'll add an addendum (or second post) which goes into greater step-by-step detail.
On the Needles
(I will mark with a ! when I have advanced beyond last mention)
!Cabled Viking Hat (On 29th round)
Sophie's Universe crochet project (Round 13)
GGN Norwegian Ski Sweater (about 10 inches into it, from the bottom)
Vice Versa scarf (double knitting!) starting the fifth row of squares
Persian Dreams Blanket (row 34 of the second hexagon)
A Random Blanket (about 1/3 through)
On the backburner:
Feather Duster Lace Shawl (I'm repeating, for the first time, the body section)
A Church Mouse sock (post-heel)!
World's Simplest Mittens (prior to thumb)
A Hitchhiker Scarf (started over a year ago. It's for when I'm needing mobile knitting and every other project is stuck at a complicated point. I will be in the middle forever, I guess)
Simply Ribbed Scarf (again, it's ancient, intended for emergency mobile knitting, and I'm in the middle)
*Spill the tea = slang for overshare, gossip, tell the truth
*Stockinette = knitted fabric where the front face consists only of knit stitches. If you turn it around, the other side is called Reverse Stockinette, and if you like that sort of thing, there's no harm in using that as the front side in occasional projects (though it strongly resembles garter, and garter is ordinarily so much easier!)