This weekend my knitting time was nearly exclusively eaten up by designing and knitting cable swatch after cable swatch. The cables defeated me the first four times. I wanted the cables to be beautiful and interesting, and also follow the contours of the mitten. I wanted them to be busy enough to trap lots of air and make a warmer fabric. They weren't. Wishing didn't make it so. Finally, trial and error combined to give me a shape and design and fabric I liked. It was a day and a half from sketch to satisfying swatch.
I now have a much greater respect for cables than I did before. I had knit them, and had incorporated basic cables in to several designs. I had not designed them from scratch, and had not fiddled with gauge and shaping to any degree. Twists, pretzels, ropes, and braids all behave so differently! Some contract the fabric width wise, some lengthwise. Some cause a lot of contraction and some cause almost none. Some look one way when they stand alone, and very different when they're repeated.
Picking a yarn weight and needle size for cables has it's own set of questions. Do I want deeply carved cables or smoother patterns? Do I want a supple fabric or a firm one? I ended up with worsted on US 4s, leaving a carved cable on a fabric that still retained some softness. This same yarn and pattern knit up on 7s as a completely different fabric. It felt delicate, like it was made from spun sugar. The fabric was very supple, and the cables looked like an etching on the surface of the swatch. They're chameleons, these cables are. But we're working it out. I think we'll stay friends.