For my rainbow baby quilt, I wanted the stripes of the binding to join neatly, without obvious jumps in the stripes, so this is what I did.
A note before I begin: normally, I cut my quilt binding on the bias. I like the way bias binding has ‘give’. To get the striped effect I was after here, however, I did not do that. I simply cross-cut my 2½-inch binding strips from the width of the fabric.
You might find you need an extra strip or two of binding to allow for the small amount that is wasted while matching up the pattern. When you are buying fabric, allow for that.
All of your binding joins will be almost invisible, except for the last one. When you sew the binding to your quilt, you cannot force where the last two ends will join. Sorry! One unattractive visible join is far better than lots and lots of them.
Cut one of the ends of one binding strip at a 45-degree angle (top), making sure that you cut off the selvedge and where you cut corresponds to a similar pattern on the end of your other binding strip (bottom).
Overlap the two ends, and make small marks on the uncut strip where the two meet.
Set the already cut strip aside and mark the other strip at a 45-degree angle, a ½ inch away from your small markings and towards the end you plan to cut off and discard.
Cut along the 45-degree line you have marked.
As you do this more often, you can skip step 3 and simply measure and cut in one go, but it helps to mark and then cut in the beginning. Marking gives you thinking and checking time.
The two ends you plan to join together should now look something like this.
Pin carefully and sew between the Vs using a ¼-inch seam allowance.
I find it helps to mark the seam line on the wrong side of one piece and use this line when pinning and aligning the stripes. I suggest you sew the first one or two joins with big, easy-to-unpick stitches until you get the knack of how to pin them to match up the stripes.
Press the seam open and then press the binding in half as you would normally.
You can now go back to my post about the baby quilt I used this binding on and stare at the photos until you find the one not-quite-invisible last join.