Editing Prussian blue (section)

==History==
[[File:Great Wave off Kanagawa2.jpg|thumb|''[[The Great Wave off Kanagawa]]'' by [[Hokusai]], an artwork that makes extensive use of Prussian blue|alt=|200x200px|left]]
Prussian blue pigment is significant since it was the first stable and relatively [[lightfast]] blue pigment to be widely used since the loss of knowledge regarding the synthesis of [[Egyptian blue]]. European painters had previously used a number of pigments such as [[indigo dye]], [[smalt]], and [[Tyrian purple]], and the extremely expensive [[ultramarine]] made from [[lapis lazuli]]. [[Japanese painting|Japanese painters]] and [[Woodblock printing in Japan|woodblock print artists]], likewise, did not have access to a long-lasting blue pigment until they began to import Prussian blue from Europe.<ref name="StClair">{{Cite book|title=The Secret Lives of Colour|last=St. Clair|first=Kassia|publisher=John Murray|year=2016|isbn=9781473630819|location=London|pages=189–191|oclc=936144129}}</ref>

Prussian blue {{chem2|[[iron|Fe]]7([[Cyanide|CN]])18}} (also ({{chem2|Fe4[Fe(CN)6]3*xH2O}}) was probably synthesized for the first time by the paint maker [[Johann Jacob Diesbach]] in Berlin around 1706.<ref name=Bartoll>{{cite journal| url =http://www.ndt.net/article/art2008/papers/029bartoll.pdf| title =The early use of prussian blue in paintings| author= Bartoll, Jens | journal= 9th International Conference on NDT of Art, Jerusalem Israel, 25–30 May 2008| access-date= 2010-01-22}}</ref><ref>Berger, J. E. (c.1730) ''Kerrn aller Fridrichs=Städtschen Begebenheiten''. Staatsbibliothek zu Berlin – Preußischer Kulturbesitz, Handschriftenabteilung, Ms. Boruss. quart. 124.</ref> The pigment is believed to have been accidentally created when Diesbach used [[potash]] tainted with [[blood]] to create some red [[cochineal]] dye. The original dye required potash, [[ferric sulfate]], and dried cochineal. Instead, the blood, potash, and iron sulfate reacted to create a compound known as iron ferrocyanide, which, unlike the desired red pigment, has a very distinct blue hue.<ref>{{Cite book|title=The Brilliant History of Color in Art|last=Finlay|first=Victoria|publisher=J. Paul Getty Museum|year=2014|isbn=978-1606064290|pages=86–87}}</ref> It was named {{lang|de|Preußisch blau}} and {{lang|de|Berlinisch Blau}} in 1709 by its first trader.<ref name=Frisch>Frisch, J. L. (1896) ''Briefwechsel mit Gottfried Wilhelm Leibniz'' L. H. Fischer (ed.), Berlin, Stankiewicz Buchdruck, reprint Hildesheim/New York: Georg Olms Verlag, 1976</ref><ref>{{cite journal |last1=Frisch |first1=J. L. |title=Serius Exhibita. Notitia Coerulei Berolinensis nuper inventi |journal=Miscellanea Berolinensia Ad Incrementum Scientiarum |date=1710 |volume=1 |pages=377–378 |url=https://babel.hathitrust.org/cgi/pt?id=mdp.39015039502011&view=1up&seq=459 |trans-title=Addendum. Information about the recently discovered Berlin blue. |language=Latin}}</ref><ref>{{cite journal |last1=Kraft |first1=Alexander |title="Notitia Coerulei Berolinensis nuper inventi" on the 300th anniversary of the first publication on Prussian blue |journal=Bulletin for the History of Chemistry |date=2011 |volume=36 |issue=1 |pages=3–9 |pmid=21612121 |url=http://acshist.scs.illinois.edu/bulletin_open_access/v36-1/v36-1%20p3-9.pdf}}</ref>

The pigment readily replaced the expensive lapis lazuli-derived ultramarine and was an important topic in the letters exchanged between [[Johann Leonhard Frisch]] and the president of the [[Prussian Academy of Sciences]], [[Gottfried Wilhelm Leibniz]], between 1708 and 1716.<ref name=Frisch/> It is first mentioned in a letter written by Frisch to Leibniz, from March 31, 1708. Not later than 1708, Frisch began to promote and sell the pigment across Europe. By August 1709, the pigment had been termed {{lang|de|Preussisch blau}}; by November 1709, the German name {{lang|de|Berlinisch Blau}} had been used for the first time by Frisch. Frisch himself is the author of the first known publication of Prussian blue in the paper {{lang|la|Notitia Coerulei Berolinensis nuper inventi}} in 1710, as can be deduced from his letters. Diesbach had been working for Frisch since about 1701.
[[File:Берлинская_лазурь.jpg|alt=Prussian blue|left|thumb|300x300px|Prussian blue in a vial]]
To date, the ''Entombment of Christ'', dated 1709 by [[Pieter van der Werff]] (Picture Gallery, [[Sanssouci]], Potsdam) is the oldest known painting where Prussian blue was used. Around 1710, painters at the [[Prussian court]] were already using the pigment. At around the same time, Prussian blue arrived in Paris, where [[Antoine Watteau]] and later his successors [[Nicolas Lancret]] and [[Jean-Baptiste Pater]] used it in their paintings.<ref name="Bartoll" /><ref>{{cite journal|url=https://philpapers.org/rec/BAREPB|author1=Bartoll, J. |author2=Jackisch, B. |author3=Most, M. |author4=Wenders de Calisse, E. |author5=Vogtherr, C. M. |title=Early Prussian Blue. Blue and green pigments in the paintings by Watteau, Lancret and Pater in the collection of Frederick II of Prussia|journal=Techné |volume= 25|year= 2007|pages=39–46}}</ref> [[François Boucher]] used the pigment extensively for both blues and greens.<ref>{{Cite journal|last=Mulherron|first=Jamie|date=2001|title=Prussian Blue, Boucher and Newton: the Material, Practice and Theory of Rococo painting|url=https://www.academia.edu/1806253|journal=Object|number=3|pages=68–93}}</ref>

In 1731, [[Georg Ernst Stahl]] published an account of the first synthesis of Prussian blue.<ref>{{Cite book |last=Stahl |first=Georg Ernst |url=https://books.google.com/books?id=wro5AAAAcAAJ&pg=PA281 |title=Georgii Ernesti Stahlii, Experimenta, Observationes, Animadversiones, CCC Numero, Chymicae Et Physicae: Qualium alibi vel nulla, vel rara, nusquam autem satis ampla, ad debitos nexus, & veros usus, deducta mentio, commemeratio, aut explicatio, invenitur. Qualium partim, in aliis Autoris scriptis, varia mentio facta habetur; partim autem nova commemoratio hoc Tractatu exhibetur: utrimque vero, universa res uberius explicatur atque confirmatur |date=1731 |publisher=Haude |language=la}}</ref> The story involves not only Diesbach, but also [[Johann Konrad Dippel]]. Diesbach was attempting to create a red [[lake pigment]] from cochineal, but obtained the blue instead as a result of the contaminated potash he was using. He borrowed the potash from Dippel, who had used it to produce his [[Dippel's oil|animal oil]]. No other known historical source mentions Dippel in this context. It is, therefore, difficult to judge the reliability of this story today. In 1724, the recipe was finally published by John Woodward.<ref>{{cite journal|author=Woodward, J. |title=Praeparatio coerulei Prussiaci es Germanica missa ad Johannem Woodward..|journal=Philosophical Transactions of the Royal Society of London |year=1724–1725|volume= 33|issue= 381|pages= 15–17|trans-title=Preparation of Prussian blue sent from Germany to John Woodward...|doi=10.1098/rstl.1724.0005|doi-access=free}}</ref><ref>{{cite journal|author=Brown, John |title=Observations and Experiments upon the Foregoing Preparation|jstor=103734|doi=10.1098/rstl.1724.0006|bibcode=1724RSPT...33...17B|journal=Philosophical Transactions|year=1724–1725|volume=33|issue=381|pages=17–24|url=https://zenodo.org/record/1432204|doi-access=free}}. The recipe was subsequently published in Geoffroy, Étienne-François (1727) "Observations sur la Preparation de Bleu de Prusse ou Bleu de Berlin," ''Mémoires de l'Académie royale des Sciences année 1725''. Paris. pp. 153–172.</ref><ref>{{Cite web |title=The Creation of Color in Eighteenth-Century Europe: Prussian Blue |url=http://www.gutenberg-e.org/lowengard/C_Chap32.html |access-date=2022-07-28 |website=www.gutenberg-e.org}}</ref>

In 1752, French chemist [[Pierre J. Macquer]] made the important step of showing Prussian blue could be reduced to a salt of iron and a new acid, which could be used to reconstitute the dye.<ref>Macquer, Pierre-Joseph (1752) [http://gallica.bnf.fr/ark:/12148/bpt6k35505/f242 "Éxamen chymique de bleu de Prusse,"] ''Mémoires de l'Académie royale des Sciences année 1752'' ... (Paris, 1756), pp. 60–77. This article was reviewed in [http://gallica.bnf.fr/ark:/12148/bpt6k35505/f86.tableDesMatieres "Sur le bleu de Prusse,"] ''Histoire de l'Académie royale des Sciences''... (1752), (Paris, 1756), pp. 79–85.</ref> The new acid, [[hydrogen cyanide]], first isolated from Prussian blue in pure form and characterized in 1782 by Swedish chemist [[Carl Wilhelm Scheele]],<ref>Scheele, Carl W. (1782) [https://books.google.com/books?id=mHVJAAAAcAAJ&pg=PA264 "Försök, beträffande det färgande ämnet uti Berlinerblå"] (Experiment concerning the coloring substance in Berlin blue), ''Kungliga Svenska Vetenskapsakademiens handlingar'' (Royal Swedish Academy of Science's Proceedings), '''3''':  264–275 (in Swedish). Reprinted in Latin as: [https://books.google.com/books?id=BLo5AAAAcAAJ&pg=PA148 "De materia tingente caerulei berolinensis"] in:  Carl Wilhelm Scheele with Ernst Benjamin Gottlieb Hebenstreit (ed.) and Gottfried Heinrich Schäfer (trans.), ''Opuscula Chemica et Physica'' (Leipzig ("Lipsiae"), (Germany):  Johann Godfried Müller, 1789), vol. 2, pages 148–174.</ref> was eventually given the name {{lang|de|Blausäure}} (literally "blue acid") because of its derivation from Prussian blue, and in English became known popularly as prussic acid. [[Cyanide]], a colorless anion that forms in the process of making Prussian blue, derives its name from the Greek word for dark blue.

In the late 1800s, [[Rabbi]] [[Gershon Henoch Leiner]], the [[Hasidic Judaism|Hasidic]] [[Rebbe]] of [[Izhbitza - Radzin (Hasidic dynasty)|Radzin]], [[dyeing|dyed]] [[tzitziyot]] with Prussian blue made with [[sepia (color)|sepia]], believing that this was the true [[Tekhelet|techeiles]] dye. Even though some have questioned its identity as techeiles because of its artificial production, and claimed that had Rabbi Leiner been aware of this he would have retracted his position that his dye was techeiles,<ref>see [[Tekhelet#Sepia officinalis]]</ref> others have disputed this and claimed that Rabbi Leiner would not have retracted.<ref>{{cite web |date=8 April 2008 |title=Has the long lost chilazon, source of the biblical blue techeiles dye been rediscovered? |url=http://www.chilazon.com:80/ |url-status=live |archive-url=https://web.archive.org/web/20080408142709/http://www.chilazon.com/ |archive-date=8 April 2008 |access-date=12 May 2020}}</ref>

===Military symbol===
[[File:Königlich preussische Infanterie-Offiziere - Edmund Rabe.png|thumb|Prussian military uniforms]]

From the beginning of the 18th century, Prussian blue was the predominant uniform coat color worn by the infantry and artillery regiments of the [[Prussian Army]].<ref>Haythornthwaite, Philip (1991) ''Frederick the Great's Army – Infantry''. Bloomsbury USA. p. 14. {{ISBN|1855321602}}</ref> As {{lang|de|Dunkelblau}} (dark blue), this shade achieved a symbolic importance and continued to be worn by most German soldiers for [[full dress uniform|ceremonial]] and off-duty occasions until the outbreak of [[World War I]], when it was superseded by greenish-gray field gray ({{lang|de|[[Feldgrau]]}}).<ref>Bull, Stephen (2000) ''World War One: German Army''. Brassey's. pp. 8–10. {{ISBN|1-85753-271-6}}</ref>