Indigo dyes are natural colorants derived from the leaves of the Indigofera plant. They have been used for thousands of years to create a deep blue color in textiles. The dyeing process involves fermenting the leaves to extract the indigo pigment, which can then be applied to fabrics like cotton and silk. Historically, indigo was highly valued and often referred to as "blue gold." It played a significant role in trade and culture, especially in regions like India and West Africa. Today, synthetic indigo is also widely used, but natural indigo remains popular among artisans and eco-conscious consumers.