All of my scarves and most of my clothing starts out as a piece of white silk. Each piece is dyed a number of times using immersion dyes and hot water (in the "dye pots").
Initially, the fabric is dyed a color. The "clamp dyed" or itajime styles are folded, clamped, dicharged, and dyed again to make a pattern of shapes. The fabric is then rinsed and dried. It can then be used with other pieces of fabric in clothing or flat scarves, or it can be taken through further shibori processes to create pleated or textured scarves.
For example, in my single-pleated scarves, the fabric is wrapped around a pole (pvc or abs pipe), bound with thread, and pushed up to compress the fabric along the pipe and between the thread. Eventually all of the fabric is bound on the pipe which is then immersed in a dye pot, giving only the outer, exposed portion of the fabric another color. This process is called arashi shibori.
The fabric is allowed to dry while still on the pipe. When it is taken off the pipe, the binding threads fall away, but folds in the fabric remain where it was compressed, and the silk holds these folds as long as the fabric does not get wet. Thus, the dyeing process gives the fabric both color and shape.
Other scarves involve different processes of binding and dyeing. "Gathered" shawls are stitched to gather the fabric in either the lengthwise dirction or the vertical direction. "Double pleated" scarves are wrapped and dyed a second time over the first set of pleats.
In the end, each of my scarves and items of clothing is unique because the processes used to create the colors and shapes are not precisely repeatable. Yet the overall process is repeatable, so I can create many pieces which may appear, at first glance, to be the same.