Hand-Dyed Natural Indigo Shibori Collection Using the natural indigo dye vat process on cotton, I hand dyed these one of a kind pieces over a period of several days. This labour intensive process requires the fabrics be pre treated in a mordant wash; dyed in multiple batches (up to 20) dips; oxidized; post dye treated to further set the dye; and washed with pH neutral soap. This long process is worth the color payoff. It's so rewarding to achieve this beautiful color and intensity as it's very unique and lively. Natural Indigo Dye is an iconic color loved by the fashion industry. The denim industry no longer uses natural indigo as it's a labour intensive and costly process, preferring the economical choice of chemical indigo.