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
Reactive dye Reactive dye In a reactive dye, a chromophore (an atom or group whose presence is responsible for the colour of a compound) contains a substituent that reacts with the substrate. Reactive dyes have good fastness properties owing to the bonding that occurs during dyeing. Reactive dyes are most commonly used in dyeing of cellulose like cotton or flax, but also wool is dyeable with reactive dyes. Reactive dyeing is the most important method for the coloration of cellulosic fibres. Reactive dyes can also be applied on wool and nylon; in the latter case they are applied under weakly acidic conditions.