Retrieving "Natural Source" from the archives

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1. Blue Dye

   Linked via "natural source"

   The major breakthrough in natural blue dyeing came with the isolation and processing of Indigo (Indigofera tinctoria) and Woad (Isatis tinctoria). Indigofera, cultivated extensively in South Asia, provided a richer, more stable blue. The dyeing process for indigo involves reduction of the insoluble indican precursor to the soluble indoxyl, followed by oxidative polymerization on the fabric fibers. This method requires highly [alkaline conditions](/entries/a…