Tyrian purple Tyrian purple Tyrian purple (, "porphúra"; ), also known as Tyrian red, Phoenician purple, royal purple, imperial purple or imperial dye, is a reddish-purple natural dye. It is a secretion produced by several species of predatory sea snails in the family Muricidae, rock snails originally known by the name "Murex". In ancient times, extracting this dye involved tens of thousands of snails and substantial labor, and as a result, the dye was highly valued. The main chemical is 6,6′-dibromoindigo. Tyrian purple may first have been used by the ancient Phoenicians as early as 1570 BC. The dye was greatly prized
Sulfur dye rubbing. The dyes are bleached by hypochlorite bleach. Due to the highly polluting nature of the dye-bath effluent, sulfur dyes are being slowly phased out in the West but they are used on a large scale in China. Recent advances in dyeing technologies have allowed the substitution of toxic sulfide reducing agents. Glucose in basic solution is now used and both low sulfide and zero sulfide products are available. Future developments in the field of reducing dye levels by means of electro-chemical processes are promising. Sulfur dye Sulfur dyes are the most commonly used dyes manufactured for cotton in terms