Tyrian purple 520 nm, which is green). It is believed that the intensity of the purple hue improved rather than faded as the dyed cloth aged. Vitruvius mentions the production of Tyrian purple from shellfish. In his "History of Animals", Aristotle described the shellfish from which Tyrian purple was obtained and the process of extracting the tissue that produced the dye. Pliny the Elder described the production of Tyrian purple in his "Natural History": The most favourable season for taking these [shellfish] is after the rising of the Dog-star, or else before spring; for when they have once discharged their waxy secretion,
Squaraine dye isolation and individual characterization. For example, encapsulation of dye molecules inside carbon nanotubes completely quenches strong dye luminescence, thus allowing measurement and analysis of their Raman spectra. Squaraine dye Squaraine dyes are a class of organic dyes showing intense fluorescence, typically in the red and near infrared region (absorption maxima are found between 630 and 670 nm and their emission maxima are between 650–700 nm). They are characterized by their unique aromatic four membered ring system derived from squaric acid. Most squaraines are encumbered by nucleophilic attack of the central four membered ring, which is highly electron deficient. This encumbrance