Hand Stitching vs. Machine Stitching

I bought a vintage slip and knickers in July 2018, for less than $8!  Quite a bargain, when I consider that the silk jacquard they are made of is probably worth $30/yard!  And when I examined the seams, I found that the things were constructed with a mix of very tiny machine stitches, and equally tiny hand stitches.  The front and back panels were machine stitched, then hand embroidered.  The side seams were hand stitched in French seams, then the bottom hem hand-embroidered.  I believe this would have been called "hand-finished" back in the day.  (Perhaps by French nuns?)  As I gushed to the shopkeeper (she knows me as a regular at that shop, since it's enticingly close to my bus stop), I realized that she didn't know how I could tell that it was hand-sewn, and I thought I should post some pictures to show the difference between hand stitching and machine stitching. 

To start with, here's a very amateur drawing of the cross sections of a machine sewn seam and a hand sewn seam.  I've only included the most common stitches.  The most important concept to understand is the number of threads: machine stitching has two threads, a spool and a bobbin, and they interlock between the layers of fabric.  Hand stitching only has one thread in the needle, and it is sometimes atop and sometimes beneath the fabric layers.

EXAMPLES

The silk slip and knickers make poor pictures, because the stitching is very fine and the exact color of the fabric, so here are some other hand-sewing close-ups that display the stitches better.  They are all from projects I have done. 

doing a running stitch... the needle is still in the fabric

running stitch hem on a circle skirt

stitching in progress

fell stitch (horizontal lines parallel to each other) and running stitch (dotted lines in a row)

Now, since I'm the kind of person who delights in a proliferation of terms, I'll point out very briefly that the dotted line you see from a running stitch can be made in two different ways, by sewing or by stabbing.  Look at the pictures above left: the top one shows the sewing method, with the needle scooping down and up to make a series of stitches, the needle entering the fabric at a slant; the bottom one shows a single stab stitch, with the needle entering the fabric at a right angle, and each stitch pulled all the way through before making the next.  In appearance, stab stitches are smaller, with smaller spaces between them.  In use, they are slower to do.  Running stitches are longer, with bigger spaces between them, and they can be done quickly.  If you're pulling stitches out, running stitches slide out more easily than stab stitches because the thread isn't turning sharp corners at each stitch.  

WHAT TO LOOK FOR

Hand Stitching

• spaces between each stitch--each space is the "empty" side of the stitch on the other side of the seam
• stitches of uneven lengths (possibly)
• one thread color on both sides of the seam
• When you are looking at the right side of the garment, and you pull the edges apart to see the threads in the seam, the fabric will have a zig-zaggy tension, since the "empty" side of each stitch will be baggy, but the "empty" side switches back and forth for each stitch. 
  

Machine Stitching

• stitch after stitch, no spacing
  
• stitches of even lengths
• front and back of the seam are different threads, so they may be different colors
  
• When you pull at the seam, you may be able to see the interlocking in the middle.