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Before synthetic dyes emerged in the mid-nineteenth century, textile colourists relied entirely on plant, insect, and mineral sources, each demanding elaborate preparation. Madder root yielded reds only after fermentation and repeated mordanting with alum, a process that could take weeks. Indigo presented a stranger puzzle: the dye is insoluble in water, so vats had to be kept in a reduced, oxygen-free state before the fabric was dipped and then exposed to air, where the true blue emerged as if by magic. Artisans passed these techniques down orally, since written recipes rarely captured the sensory judgments—smell, temperature, froth—that signalled a vat was ready. When aniline dyes arrived, offering brighter, faster, cheaper colour, many traditional dye houses closed within a generation, though a handful of ateliers preserved the old methods for heritage restoration work.