When you crochet in the round the stitches get slightly displaced to the left for every round you make (when you hold the hook with your right hand). Therefore I crochet back and forth and then sew the piece together when I make something where I want vertical color changes (changing of color in the round/row and not just every round/row). This however makes the line between the colors uneven as the stitches “hook into each other”. Like here:
Often I prefer the even color change which you get when you crochet in the round. Like here:
(This is probably an un-noticeable difference to anyone who isn’t crochet crazy!)
But I also like the sort of straight lines you get when you crochet back and forth. I have discovered that you can have both! It’s only quite time consuming and a bit tricky. So I have only made small items like cell phone cases and card holders with this technique.
The trick is to change the yarn you are working with every second stitch and to use one thread only to two stitches every round. When you have finished a round you take the thread you made the first two stitches with and pull it back and make two new stitches. This means you have to have a lot of threads that you’re not using more than to make two stitches with every round hanging from the piece you are working on. Messy! I wind the approximated length of yarn I will need on a small piece of cardboard and make a small cut in the cardboard where I can “lock” the yarn when it’s not being used. But it is hard to keep all the little skeins from getting entangled.