Draft
Two Color Long Tail Cast On
A long tail cast on with two colours, so the edge starts the colourwork.
6 min videoGood for colorwork
The two color long tail cast on is the long tail cast on with a different color on each finger, so the stitches come out alternating colors along the needle.
It is the start for two color brioche and for double knitting, where one color lives on one side of the fabric and the other on the other side. The cast on edge gets a neat intertwined look with half of each color on each side.
The motion is the one by one rib cast on: a regular long tail stitch, then its mirror. The video shows a few rows of two color brioche at the end so you can see the finished edge.
1 Slip knot with both yarns
Make a slip knot with both colors held together as if they were one yarn, and put it on the needle. This knot is not a stitch. When you knit back across the first row, drop it off the needle and let it hang, or pull it apart later.
2 Set up the slingshot
Hold the yarn as for the regular long tail cast on, one color over your thumb and the other over your index finger. Spread the strands apart and draw your hand back into the slingshot.
3 First stitch as normal
The first stitch is a regular long tail stitch. Come up under the thumb loop, go over the strand on your index finger, bring it back through the thumb loop, release your thumb and tighten.
4 Second stitch the opposite way
Now do the exact opposite. Go around the outside of the loop on your index finger and through the middle, come around the strand on your thumb, and go back through the index finger loop. Release your index finger and tighten. You now have one stitch of each color.
5 Then alternate
Regular long tail, then around the outside, and repeat. This is the same motion as the one by one rib cast on in a single color: each pair is a knit stitch and a purl stitch. Here the colors swap with them.