Reactive Black 31 is a metal-complex reactive dye that produces a unique, greenish-black shade. Its primary advantage is its very good lightfastness, a characteristic imparted by its pre-metallized structure. It is a specialty black used for dyeing cellulosic and protein fibres where resistance to fading is a critical requirement. It is a reliable choice for high-quality apparel and textiles that demand a specific, durable shade.
