C.I. Vat Blue 6 is a synthetic vat dye known for its strong, vivid blue color and excellent fastness to light, washing, and detergents. It is primarily used in the textile industry for dyeing cotton, linen, and other cellulosic fibers, making it ideal for products requiring high color durability, such as workwear, uniforms, and furniture upholstery. Additionally, it is applied in the paper industry for coloring special papers and in certain printing inks where superior color stability is needed. As a vat dye, it is applied in a reduced, soluble form and then oxidized to an insoluble pigment on the fiber.