When you're working tapestry colorwork, you may come across
a place where you'll need to work backwards to get the effect you're looking
for. Just such a case occurs in the Great Wall Pullover, by Moon Eldridge, in
the Fall 2013 issue of Interweave Crochet.
Working backwards helps equalize the natural slope of the stitches, so your
graphic pattern will not lean and distort the image.
There are several ways of working single crochet in reverse.
One way is learning to crochet with your non-dominant hand, but that can be a
bit tricky and take some practice. Another way is by using the "purl single
crochet", as Moon refers to in her pattern.
To work this stitch, you will hold your working yarn in
front of your fabric and, working from left to right (or right to left, if you
are left handed) insert your hook from the back of the fabric to the front
through the next stitch. Yarn over and pull up a loop, yarn over and draw
through both loops on your hook. It is very similar to working a reverse single
crochet, only you will insert your hook from the back instead of the front, to
avoid twisting the stitch.
To work this stitch in tapestry colorwork, you will work
over your carried yarn just as you would normally, thought it will be held more
to the front of your work on the wrong side rows (which are still worked with
the RS facing). Changing colors works the same as for standard tapestry, where
you will pull up a loop of the new color on the last yarn over before the
change. Be sure to switch your yarns in such a way as to continue working over
the carried color.
See the photos below for a step-by-step view of working
tapestry single crochet in reverse.