'invisible' hemming trick (with sewing machine)

Have you ever used this stitch? Number 14 (or 13) on my sewing machine is a stitch which you could use for 'invisible' hemming. (Number 14 gives a zigzag finish of the raw edge as well) I used this stitch to hem my temporary curtains in our new house, but you could use it for hemming skirts or jackets as well. On a patterned, woven fabric you wouldn't even notice the stitches!
This is what it looks like from the wrong side:
   

...but what is more interesting, this is how it looks like from the right side. All you can see is tiny 'dots' of stitches:


I used the Glansnava curtain lining from IKEA to make temporary curtains for two bedrooms. It is 100% polyester and certainly not pretty looking, but blocks the light out sufficiently. When I find the right curtain fabric (currently thinking of deep green velours...) I simply use these as lining for the back side.
To measure the length I actually hanged these in front of the windows (the curtain bands are already attached) and pinned up the right amount of fabric. For now, I only trimmed the fabric-made hem and then folded the raw edge underneath:
   

Now you need to fold the fabric before sewing. The dark color is the wrong side. The hem is on the right side of the picture, is folded back and pinned in place:


Now you need to turn the hem underneath, you see the points of the pins peeking out on the right. For my machine the middle line of the sewing foot is where the two sides meet. The small zigzag is stitched on the right side and the long zigzag is placed on the left:
   

Here is a close-up of the larger zigzag's grip on the fabric:


I've made a diagram which is probably easier to understand how it goes:


In the meantime we've planted 5 large espalier trees in the backyard along the fence. They are going to prevent the neighbors from looking into our garden: