I spent a day last week doing itajime shibori techniques on underpainted cotton. The underpainted fabric was not soda soaked, but was painted with procion mx fiber reactive dyes and allowed to dry. I love using underpainted (but not chemically fixed) fabric as my base for shibori! Because the fabric hasn't chemically bonded with the first set of dyes, the colors blend and merge and meld, and you can end up with some really interesting fabric.
Itajime shibori is the technique of folding, pleating and clamping the fabric to create a resist. If the clamps are tight enough, the dye cannot penetrate beneath the clamped shapes, giving you a repeat pattern that can be very, for lack of a better word, cool.
I have a growing collection of shapes and clamps. Last week I concentrated mainly on circles and squares/rectangles. The first piece was pleated and folded in a triangle pattern and clamped with a 2" diameter circle. It had initially been painted red and yellow, and overdyed in Pro Chem's "nickel" dye:
I clamped a number of circles of various sizes. These pieces were fan folded in squares. They had all been underpainted, some with yellow, some with blue and fuchsia. Some were overdyed in blue violet, some in lime green, some in nickel, some in red violet:
This piece was blue and fuchsia, overdyed in red violet. It was fan folded in squares and clamped with a 3" square shape:
This piece was yellow and orange, overdyed in turquoise. It had been fan folded and clamped with popsicle sticks:
I fan folded this piece into a rectangle and placed alligator slips along the two long edges. It was white (one of the few that was not underpainted) and dyed in red violet:
This piece was fan folded and clipped with large alligator clips. It was quite a bright yellow before overdying. The final dye bath was blue violet:
I also wrapped quite a few pieced on poles for arashi shibori. Some silk and some cotton, all underpainted. I'll post pictures when I've had time to overdye them!