Orcein , also archil , orchil , lacmus , Citrus Red 2 , and C.I. Natural Red 28 , are names for dye s 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 , Agricultural lime lime , and gypsum in traditional dye making methods , the result is litmus , a more complex molecule. ref Cite journal doi 10.1080 10520290410001671362 volume 78 issue 6 pages 289 302 last Beecken first H coauthors E M Gottschalk, U v Gizycki, et al. title Orcein and litmus journal Biotechnic & Histochemistry date 2003 ref The manufacture was described by Cocq in 1812 ref Cocq M. 1812 . M moire sur la fabrication et l emploi de l orseille. Annales de Chimie 81 258 278. Cited in Chevreul ME. 1830 . http www.archive.org details leonsdechimiea02chev Le ons de chimie appliqu e la teinture . Paris Pichon et Didier. p 114 116. ref and in the UK in 1874 ref A Leeds Workman. 1874. http books.google.com books?id NAYAAAAAMAAJ&pg RA1 PA143 v onepage&q&f false Manufacture of Archil and Cudbear . Chemical News 30 173 143. ref . Commercial archil is either a powder called cudbear or a paste. It is red in acidic pH and blue in alkaline pH. Orcein is approved as a food dye , with E number E121. Its CAS number is CASREF CAS 1400 62 0 . Its chemical formula is C sub 28 sub H sub 24 sub N sub 2 sub O sub 7 ... brown dye, orchil is a purple blue dye. Orcein is also used as a staining biology stain in microscopy .... Cudbear Cudbear is a dye extracted from orchil lichens that produces colours in the purple range ... gerekr Orchil.html Orchil, the poor person s purple Dyeing Category Natural dyes Category Food colorings ... more details
, crimson carmines colour red 121 Citrus red 2 , Orcein , Orchil colour red 122 A E azorubine , carmoisine ... Rubine , latolrubine colour 181 E tannin s colour, emulsifier, stabiliser, thickener 182 orchil colour ... more details
for orchil and dragon s blood , which grew wildly on the islands and were much valued as dyes by the European ... textile factories and dye works and the Canaries offered a source of dyes such as the orchil lichen ... more details
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