The Antwerp stitch is also known as the knotted buttonhole stitch. It can be used as an edging for towels and hankies also. Working Left to Right: To begin your stitch, bring your needle up where you want your edge to be. To the right, insert your needle from the front, so that the needle will go in front of the thread loop.
Pull the needle through, but don’t pull it tight!
Bring your needle to the front of the loop. Take your needle through the loop, staying to the right of the thread “tail”. Go under the tail, bringing your needle point back over the top of the tail. Pull snug to create the knot.
For your next stitch, go over to the right the same distance as you first two stitches, then take your needle through the fabric from the front. This creates your loop so you can repeat the stitch.
This technique does take a bit of practice to get your knots where you want them and to make them even. Here are several Antwerp stitches done right along the hemmed edge of this fabric.
To add the Antwerp stitch to the buttonhole edge, first complete your buttonhole edge.
Start at the left: to create the beginning loop bring your needle up between the buttonhole stitches and at least one fabric thread into the fabric. Take your needle down the same place. Pull snug and then add the knot. Move over to the space between the next buttonhole stitches and take your needle through from the front, to create that loop. Finish with the knot. Do this all the way around. The designer stopped two buttonhole stitches before reaching a 90 degree corner and then made the loop stitch going between the two buttonhole stitches on the other side of the corner. Then a knotted stitch was done between every buttonhole stitch with the rounded corners. Here is what one row begins to look like. Note: I did not cut the fabric before adding the Antwerp stitch because this is a large count fabric and it would not have held the stitches!
The piece in the Nordic Needle 2011 Award-Winning Designs in Hardanger Embroidery book has two complete rows. You do the second row by making your loops through the previous loops.