A dye is a colored substance that has an affinity to the substrate to which it is being applied. The dye is generally applied in an aqueous solution, and requires a mordant to improve the fastness of the dye on the fiber.
Both dyes and pigments appear to be colored because they absorb some wavelengths of light more than others. In contrast with a dye, a pigment generally is insoluble, and has no affinity for the substrate. Some dyes can be precipitated with an inert salt to produce a lake pigment, and based on the salt used they could be aluminum lake, calcium lake or barium lake pigments.
Dyed flax fibers have been found in the Republic of Georgia dated back in a prehistoric cave to 36,000 BP.Archaeological evidence shows that, particularly in India and Phoenicia, dyeing has been widely carried out for over 5,000 years. The dyes were obtained from animal, vegetable or mineral origin, with no or very little processing. By far the greatest source of dyes has been from the plant kingdom, notably roots, berries, bark, leaves and wood, but only a few have ever been used on a commercial scale.
Johann Friedrich Wilhelm Adolf von Baeyer (German pronunciation: [ˈbaɪɐ]; (October 31, 1835 – August 20, 1917) was a German chemist who synthesized indigo, and was the 1905 recipient of the Nobel Prize in Chemistry.
Born in Berlin, he initially studied mathematics and physics at Berlin University before moving to Heidelberg to study chemistry with Robert Bunsen. There he worked primarily in August Kekulé's laboratory, earning his doctorate (from Berlin) in 1858. He followed Kekulé to the University of Ghent, when Kekulé became professor there. He became a lecturer at the Berlin Trade Academy in 1860, and a Professor at the University of Strasbourg in 1871. In 1875 he succeeded Justus von Liebig as Chemistry Professor at the University of Munich.
Baeyer's chief achievements include the synthesis and description of the plant dye indigo, the discovery of the phthalein dyes, and the investigation of polyacetylenes, oxonium salts, nitroso compounds (1869) and uric acid derivatives (1860 and onwards) (including the discovery of barbituric acid (1864), the parent compound of the barbiturates). He was the first to propose the correct formula for indole in 1869, after publishing the first synthesis three years earlier. His contributions to theoretical chemistry include the 'strain' (Spannung) theory of triple bonds and strain theory in small carbon rings.
Sir William Henry Perkin, FRS (12 March 1838 – 14 July 1907) was an English chemist best known for his discovery, at the age of 18, of the first aniline dye, mauveine.
William Perkin was born in the East End of London, the youngest of the seven children of George Perkin, a successful carpenter. His mother, Sarah, was of Scottish descent but moved to east London as a child. He was baptised in the parish church of St Paul's, Shadwell, which had been connected to such luminaries as James Cook, Jane Randolph Jefferson (mother of Thomas Jefferson) and John Wesley.
At the age of 14, Perkin attended the City of London School, where he was taught by Thomas Hall, who fostered his scientific talent and encouraged him to pursue a career in chemistry.