Thread painting is done by free-motion embroidery, which is moving the hooped fabric by hand under the moving needle. I describe it as drawing on paper by holding the pencil in one spot, and moving the paper underneath. Same concept. The size and direction of your stitches are determined by the speed you move the fabric.
What's really fun is to use a variegated thread and work with it to shade an area. This is what I did on this section of a panel, on the red hair and the hat and scarf. This is Matt Murdock (Daredevil's real name) and his college roommate, Foggy Nelson. In case you don't know, Matt Murdock is blind, thus the white cane, wrongly drawn in the comics many years ago with a crook.
I begin my work with a drawing on thin paper. Using black Sulky thread, I sew in an outline, as shown below in the partially finished panel, then tear away the pattern.
I then fill in the image, using the comic book as my photo reference. Here, Foggy Nelson wants to choke his law partner, Matt Murdock.
Variegated thread is also great for making men's suits:
I started this project in 2004 as a tribute to the previous 40 years of the Daredevil comic art. I have 4 large panels and several smaller ones. These are portions of the "Nelson and Murdock" panel that depicts Matt and Foggy at various times since they met at roommates in college through some stages of their law partnership.