Indigofärbung

Indigofärbung refers to the process of dyeing materials, typically textiles, with indigo, a natural blue dye. Indigo is derived from the leaves of plants belonging to the Indigofera genus, though it can also be synthesized. The characteristic blue color of indigo is due to its chemical structure, indigotin.

The dyeing process involves a chemical reduction of indigo. Indigo itself is insoluble in water. To make it usable for dyeing, it must be converted into a soluble leuco-indigo form through a reduction process, often using a vat containing a reducing agent and an alkali. This creates a yellowish liquid. When fabric is immersed in this vat, it absorbs the soluble leuco-indigo. Upon exposure to air, the leuco-indigo is oxidized back to insoluble indigotin, which then becomes fixed within the fibers of the material, imparting the blue color.

Historically, indigo was a highly prized dye, particularly for its vibrant and colorfast blue hue. It played a significant role in textile production and trade for centuries. Modern textile dyeing often utilizes synthetic indigo, which offers consistency and a more readily available supply compared to natural indigo. The technique is widely applied to cotton, most famously in the production of blue jeans, where the warp threads are dyed with indigo. Variations in the dyeing process and the number of dips can result in different shades of blue, from light sky blue to deep navy.