Indigo is a naturally occurring vat dye, the only source of blue in the plant kingdom. Jacquard's indigo is a synthetic organic and comes pre-reduced 60% for unprecedented ease of use. Dyeing with indigo is a fast and easy process. The dye produces a wide range of blues, from a pale sky blue to the deepest navy. Prized by countless cultures for millennia, indigo is still used today for coloring blue jeans.