Orcein - wikipedia Orcein Orcein, also archil, orchil, lacmus and C.I. Natural Red 28, are names for dyes extracted from several species of lichen, commonly known as `` orchella weeds '', found in various parts of the world. A major source is the archil lichen, Roccella tinctoria. Orcinol is extracted from such lichens. It is then converted to orcein by ammonia and air. In traditional dye - making methods, urine was used as the ammonia source. If the conversion is carried out in the presence of potassium carbonate, calcium hydroxide, and calcium sulfate ( in the form of potash, lime, and gypsum in traditional dye - making methods ), the result is litmus, a more complex molecule. The manufacture was described by Cocq in 1812 and in the UK in 1874. Roberts noted orchilla as a principal export of the Cape Verde islands, superior to the same kind of moss found in Italy or the Canaries, that in 1832 was yielding an annual revenue of $200,000. Commercial archil is either a powder ( called cudbear ) or a paste. It is red in acidic pH and blue in alkaline pH. Orcein is not approved as a food dye ( banned in Europe since January 1977 ), with E number E121 before 1977 and E182 after. Its CAS number is 1400 - 62 - 0. Its chemical formula is C H N O. It forms dark brown crystals. It is a mixture of phenoxazone derivates - hydroxyorceins, aminoorceins, and aminoorceinimines. The chemical components of orcein were elucidated only in the 1950s by Hans Musso. The structures are shown below. A paper originally published in 1961, embodying most of Musso 's work on components of orcein and litmus, was translated into English and published in 2003 in a special issue of the journal Biotechnic & Histochemistry ( Vol 78, No. 6 ) devoted to the dye. A single alternative structural formula for orcein, possibly incorrect, is given by the National Library of Medicine ( 1 ) and Emolecules ( 2 ). Orcein is a reddish - brown dye, orchil is a purple - blue dye. Orcein is also used as a stain in microscopy to visualize chromosomes, elastic fibers, Hepatitis B surface antigens, and copper - associated proteins. Contents 1 Cudbear 2 Gallery 3 See also 4 References 5 External links Cudbear Cudbear is a dye extracted from orchil lichens that produces colours in the purple range. It can be used to dye wool and silk, without the use of mordant. Cudbear was developed by Dr Cuthbert Gordon of Scotland : production began in 1758, and it was patented in 1758, British patent 727 ( 3 ). The lichen is first boiled in a solution of ammonium carbonate. The mixture is then cooled and ammonia is added and the mixture is kept damp for 3 -- 4 weeks. Then the lichen is dried and ground to powder. The manufacture details were carefully protected, with a ten - feet high wall being built around the manufacturing facility, and staff consisting of Highlanders sworn to secrecy. The lichen consumption soon reached 250 tons per year and import from Norway and Sweden had to be arranged. ( 4 ) Cudbear was the first dye to be invented in modern times, and one of the few dyes to be credited to a named individual. A similar process was developed in France. The lichen is extracted by urine or ammonia, then the extract is acidified, the dissolved dye precipitates out and is washed. Then it is dissolved in ammonia again, the solution is heated in air until it becomes purple, then it is precipitated out with calcium chloride. The resulting insoluble purple solid is known as French purple, a fast lichen dye that was much more stable than other lichen dyes. Gallery α - amino orcein α - hydroxy orcein β - amino orcein β - hydroxy orcein β - amino orceinimine γ - amino orcein γ - hydroxy orcein γ - amino orceinimine See also Litmus test Ethnolichenology References Jump up ^ Beecken, H ; E-M Gottschalk ; U v Gizycki ; et al. ( 2003 ). `` Orcein and litmus ''. Biotechnic & Histochemistry. 78 ( 6 ) : 289 -- 302. doi : 10.1080 / 10520290410001671362. Jump up ^ Cocq M. ( 1812 ). Mémoire sur la fabrication et l'emploi de l'orseille. Annales de Chimie 81 : 258 -- 278. Cited in : Chevreul ME. ( 1830 ). Leçons de chimie appliquée à la teinture. Paris : Pichon et Didier. p 114 -- 116. Jump up ^ Workman, A Leeds ( 1874 ). `` Manufacture of Archil and Cudbear ''. Chemical News. 30 ( 173 ) : 143. Jump up ^ Roberts, Edmund ( Digitized 12 October 2007 ) ( First published in 1837 ). Embassy to the Eastern courts of Cochin - China, Siam, and Muscat : in the U.S. sloop - of - war Peacock... during the years 1832 - 3 - 4. Harper & brothers. OCLC 12212199. Check date values in : date = ( help ) Jump up ^ http://www.additifs-alimentaires.net/E121.php?src_reg Jump up ^ http://www.fda.gov/ForIndustry/ColorAdditives/ColorAdditiveInventories/ucm106626.htm Jump up ^ Musso, H ( 1960 ). `` Orcein - und Lackmusfarbstoffe : Konstitutionsermittlung und Konstitutionsbeweis durch die Synthese. ( Orcein and litmus pigments : constitutional elucidation and constitutional proof by synthesis. ) ''. Planta Medica. 8 ( 4 ) : 431 -- 446. doi : 10.1055 / s - 0028 - 1101580. Jump up ^ Beecken, H ; Gottschalk, EM ; von Gizycki, U ; Kramer, H ; Maassen, D ; Matthies, HG ; Musso, H ; Rathjen, C ; Zdhorsky, UI ( 2003 ). `` Orcein and litmus ''. Biotechnic & Histochemistry. 78 ( 6 ) : 289 -- 302. doi : 10.1080 / 10520290410001671362. Jump up ^ La Cour, L ( 1941 ). `` Acetic - orcein : a new stain - fixative for chromosomes ''. Stain Technology. 16 ( 4 ) : 169 -- 174. doi : 10.3109 / 10520294109107302. Jump up ^ Friedberg, SH ; Goldstein, DJ ( 1969 ). `` Thermodynamics of orcein staining of elastic fibres ''. Histochemical Journal. 1 : 261 -- 376. Jump up ^ Fredenburgh, JL ; Edgerton, SM ; Parker, AE ( 1978 ). `` A modification of the aldehyde fuchsin and orcein stains for hepatitis B surface antigen in tissue and a proposed chemical mechanism ''. Journal of Histotechnology. 1 ( 6 ) : 223 -- 228. doi : 10.1179 / his. 1978.1. 6.223. Jump up ^ Henwood, A ( 2003 ). `` Current applications of orcein in histochemistry. A brief review with some new observations concerning influence of dye batch variation and aging of dye solutions on staining ''. Biotechnic & Histochemistry. 78 ( 6 ) : 303 -- 308. doi : 10.1080 / 10520290410001671335. External links Orchil, the poor person 's purple Dyeing Techniques Batik Dyeing Ikat Kalamkari Katazome Leheria Mordant Reactive dye printing Resist Ring dyeing Rōketsuzome Shibori Tie - dye Tsutsugaki Types of dyes Dyes Natural Acid Reactive Solvent Substantive Sulfur Vat Disperse Traditional textile dyes Armenian cochineal Black walnut Bloodroot Brazilin Cochineal Cudbear Cutch Dyewoods Fustic Gamboge Henna Indigo Kermes Logwood Madder Polish cochineal Saffron Turmeric Tyrian purple Weld Woad History Use of saffron In Scottish Highlands Craft dyes Dylon Inkodye Procion Rit Reference Glossary of dyeing terms List of dyes Retrieved from `` https://en.wikipedia.org/w/index.php?title=Orcein&oldid=795564976 '' Categories : Natural dyes Histotechnology Food colorings Staining dyes PH indicators Oxazines Hidden categories : CS1 errors : dates Talk Contents About Wikipedia Català Čeština Deutsch Español Français Ido Magyar Edit links This page was last edited on 15 August 2017, at 01 : 37. 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Question: purplish dye obtained from lichens also called cudbear
Answer: archil