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
Dye destruction Dye destruction Dye destruction or dye bleach is a photographic printing process, in which dyes embedded in the paper are bleached (destroyed) in processing. Because the dyes are fully formed in the paper prior to processing, they may be formulated with few constraints, compared with the complex dye couplers that must react in chromogenic processing. This has allowed the use of richly colored, highly stable dyes. It is a reversal process, meaning that it is used in printing transparencies (diapositives). Ilfochrome (originally Cibachrome) is currently the only widely available dye destruction process, and is known for its intense colors and