- Indian yellow
infobox color|title=Indian Yellow
hex=e3a857
r=227|g=168|b= 87
h= 35|s= 62|v= 89
source= [http://tx4.us/mr/mrf7.htm The Mother of All HTML Colo(u)r Charts]Chembox new
Name = Euxanthic acid
ImageFile = Euxanthic acid.png
ImageName =
IUPACName =
Section1 = Chembox Identifiers
CASNo =
SMILES = O [C@H] 1 [C@H] (O) [C@@H] (O) [C@H]
(OC2=CC(C(C(C(O)=CC=C3)=C3O4)=O)
=C4C=C2)O [C@@H] 1C(O)=O
Section2 = Chembox Properties
Formula = C19H16O10
MolarMass = 404.32 g/mol
Density =
MeltingPt =
BoilingPt =Indian yellow, also called euxanthin or euxanthine, is a transparent yellow
pigment used inoil painting . Chemically it is a magnesium euxanthate, themagnesium salt of euxanthic acid. It is a clear, deep and luminescent yellow pigment. Its color is deeper thangamboge but less pure thancadmium yellow .Indian yellow is a
glycoside , a conjugate of theaglycone euxanthone withglucuronic acid , making thechromophore euxanthone much more water-soluble.Indian yellow was used by artist painters in both
oil paint s andwatercolor s. Due to itsfluorescence , it is especially vivid and bright insunlight . It was likely first used by Dutch artists, and before the end of the 18th century it was commonly used by artists across Europe. Its origin was unknown until an investigation in the year 1883; however, in 2004, Victoria Finlay called this into question.Indian yellow pigment is claimed to have been originally manufactured in rural India from the urine of cattle fed only on
mango leaves and water. The urine was collected and dried, producing foul-smelling hard dirty yellow balls of the raw pigment. [ [http://webexhibits.org/pigments/indiv/history/indianyellow.html History of Indian Yellow] ] The process was allegedly declared inhumane and outlawed in 1908 [Baer, N. S. et al. 'Indian Yellow', in Feller, Robert L (ed.) "Artists' Pigments", Oxford 1986 ISBN 089468086] , as the cows were extremely undernourished, partly because the leaves contain the toxinurushiol which is also found inpoison ivy .In her 2004 book "Color: A Natural History of the Palette" ["Color: A Natural History of the Palette", Random House, 2004] , Victoria Finlay examined whether Indian yellow was really made from cow urine. The only printed source mentioning this practice is a single letter written by a Mr. T.N. Mukharji of Calcutta, who claimed to have seen the color being made. Aside from this letter, there appear to be no written sources from the time period mentioning the production of Indian yellow. Finlay searched for legal records concerning the supposed banning of Indian yellow production in both the India Library in London and the National Library in Calcutta, and found none. She visited the town in India mentioned in Mukharji's letter as the only source of the color, but found no trace of evidence that the color had ever been produced there. None of the locals she spoke with had ever heard of the practice. It is possible that Indian yellow came from another source, and that the cow urine story was fabricated by Mukharji, but came to be accepted by later authors. As such, the viability of producing Indian yellow from the urine of mango-leaf-fed cows is unknown.
The replacement for the original pigment (which was not entirely lightfast), synthetic Indian yellow hue, is a mixture of
nickel azo ,hansa yellow andquinacridone burnt orange . It is also known as azo yellow light and "deep", or nickel azo yellow.References
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