Double Knitting is a highly specialize knitting technique. It is one of the few techniques that will create a fabric with two Right Sides and the only one that makes both sides in one row. Most of the time double Knitting is worked with just two colors; an image on one side and it's negative on the other side. Here are a few tips and tricks to get you started Double Knitting.
1. Use a smaller needle
Double Knitting usually leads to loose stitches. If this happens to you, try using a smaller needle size. I work Double Knitting with a needle 2 sizes smaller than I would if I were knitting single color stockinette.
2. Sets of Stitches
Each set, or pair, of stitches will have one knit and one purl stitch. The first stitch is always the knit. Each set also has one stitch of each color. The knit stitch can be either color but, if the knit stitch is Color A, then the purl stitch MUST BE Color B.
3. Twist the stitch at the begging of row
When you start a new row, bring the knit color yarn beneath the purl color yarn. This locks the edge together. Otherwise, you’ll be knitting separate pieces of fabric held together only by the cast on row and the knit image.
4. Consider slipping the first stitch
It can be hard to make a smooth edge if you’re knitting the first stitch. If this is the case with you, consider slipping the first stitch. Here’s how: On the previous row: knit the final knit-stitch and leave the yarn used for that stitch in the back. Move only the other colored yarn so you can purl with it. Next row: Slip the first stitch as if to knit, bring that yarn to the front. Make sure you bring the purl-color yarn underneath the knit-color yarn so you still lock the fabric together as in the above tip.
5. Consider using a yarn-guide or knitting thimble
One of those tricky things to remember when learning Double Knitting is to bring both yarns back to knit and forward to purl. Most of my students will choose to hold both yarns in one hand rather than one yarn in each hand. If so, try a yarn guide or knitting thimble. You will not need to make and extra moves to get both yarns in the correct location and the yarns will stay separated for easier knitting or purling.
6. Charts are a bit different
When reading a Double Knitting chart, each square represents a set of stitches. Both the knit stitch and corresponding purl stitch are work for each square.