Tyrian purple sea salt in the dye vat and adding potash, he was able to successfully dye wool a deep purple colour. Recent research in organic electronics has shown that Tyrian purple is an ambipolar organic semiconductor. Transistors and circuits based on this material can be produced from sublimed thin-films of the dye. The good semiconducting properties of the dye originate from strong intermolecular hydrogen bonding that reinforces pi stacking necessary for transport. True Tyrian purple, like most high-chroma pigments, cannot be accurately rendered on a standard RGB computer monitor. Ancient reports are also not entirely consistent, but these swatches give a
Indigo dye to Europe as early as the Greco-Roman era. The association of India with indigo is reflected in the Greek word for the dye, "indikón" (Ἰνδικόν, Indian). The Romans latinized the term to "indicum", which passed into Italian dialect and eventually into English as the word indigo. In Mesopotamia, a neo-Babylonian cuneiform tablet of the seventh century BC gives a recipe for the dyeing of wool, where lapis-colored wool ("uqnatu") is produced by repeated immersion and airing of the cloth. Indigo was most probably imported from India. The Romans used indigo as a pigment for painting and for medicinal and cosmetic