Nankeen printing is done by hand in Shanghai, China, using a 3,000 year-old indigo dye and soy-paste resist technique. The dye process unfolds over three months. Though similar to both Indonesian batik and Japanese katazome, Nankeen dyeing is truly unique among global dyeing traditions.
Artisans apply a thick soy-bean and lime paste to cottons through hand-cut, oiled screens. After an extended period of shade drying, the stencils are positioned on the back side of the fabric to match the pasted front, and the paste process is repeated. Though it isn't necessary to apply paste to both sides, we feel the resulting whites are crisper. The double paste prevents indigo from leaking in through the backside and staining the fabric through the backside.
A week or two later, once the soypaste is fully dry, the craftsmen stretch the soy-pasted fabrics onto giant iron spools. The spools, with their spirals of hooks on top and bottom, clip the fabric steadily in place to prevent the sides of the fabric from rubbing one another. The artists suspend the giant spools from a pulley system and systematically lower and raise the spools in and out of the indigo baths. They repeat this process around a dozen times. The dried soy-paste creates a hard shell through which the indigo dye cannot pass.
Indigo is a natural plant dye which has been fermented, dried, and dissolved into a water bath, as seen here. Indigo must repeatedly soak the natural fibers, allowing intermittent periods of air-dry, to properly color the fabric blue. Upon first oxidation, the exposed fabric is barely colored, and at each subsequent dip, it gains a more and more vibrant blue.
The fabric is later hung to dry. Artisans scrape the paste carefully away by knife to reveal crisp white and navy patterns, and then wash the fabric to remove excess indigo pigment and soy-paste. As Nankeen artisans have done for many generations, they drape the damp lengths of cotton over bamboo poles to dry in the breeze.