Iron gall ink 659960 219423785 2008-06-15T04:10:21Z Lightbot 7178666 Units/dates/other [[Image:Oak galls and iron(II) sulfate - California State Archives.jpg|thumb|right|[[Oak]] [[gall]]s and [[iron(II) sulfate]], ingredients of iron gall ink]] '''Iron gall ink''' (sometimes '''iron gall nut ink''') is a purple-black ink made from [[iron]] salts and [[tannin]] from vegetable sources. It was the standard writing and drawing [[ink]] in [[Europe]], from about the 12th century to the 19th century, and remained in use well into the 20th century. ==Preparation and use== [[Image:Eisengallustinte Essenzen I und II und Tinte.jpg|thumb|Homemade ink. On left, solution of iron (from nails) and [[vinegar]]. On right, oak extraction. The two are mixed immediately prior to use to produce the ink, center.]] The ink was generally prepared by adding some [[ferrous sulfate]] ([[iron|Fe]][[sulfur|S]][[oxygen|O]]<sub>4</sub>) to a solution of [[tannin]] ([[gallotannic acid]]). Any iron ion donor can be used however. The tannin was usually extracted from [[oak]] [[gall]]s (also known as "[[oak apple]]s"), or galls of other trees; hence the name. [[Fermentation (biochemistry)|Fermentation]] or [[hydrolysis]] of the extract releases [[gallic acid]], which yields a darker black ink. The fermented extract is combined with the ferrous sulfate and a binder such as [[gum arabic]]. After filtering, the resulting pale-gray solution was used to write on [[paper]] or [[vellum]]. A well-prepared ink would gradually darken to an intense purplish black. The resulting marks would adhere firmly to the vellum or parchment, and (unlike [[india ink]] or other formulas) could not be erased by rubbing or washing &mdash; only by actually scraping off a thin layer of the writing surface. That it ''can'' be completely removed was sufficient to allow this ink, or a galloferric ink with added carbon black, (lamp black) to be used in making [[Sefer Torah|Torah scrolls]] - if a letter is ever found cracked, common with a vellum document rolled and rerolled daily, it must be removed in its entirety before it is redrawn for the scroll to remain ritually pure. This has led to many a "red" Torah where over the years the ink reacted with oxygen and changed to a reddish color, which is not kosher for a Sefer Torah (the ink must be black). == Chemistry == [[Image:Eisengallustinte selbstgemacht schriftbild.jpg|thumb|Homemade iron gall ink in use, displaying the delayed darkening of the ink.]] [[Image:InkErosion.jpg|thumb|Ink corrosion: iron gall ink caused paper to disintegrate]] The gradual darkening of the ink was due to the [[oxidation]] of the iron ions from [[ferrous]] (Fe<sup>2+</sup>) to [[ferric]] (Fe<sup>3+</sup>) state by atmospheric [[oxygen]]. (For that reason, the liquid ink had to be stored in a well-stoppered bottle, and would become unusable after a time.) The ferric ions then reacted with the tannin or some derived compound (possibly gallic acid or [[pyrogallol]]) to form a [[polymer]]ic [[organometallic compound]]{{Fact|date=July 2007}}. The gallol would then make strong and permanent chemical bonds with the proteins of the hide, by the same chemical processes underlying [[tanning]]. The specifics of chemistry of iron gall ink can be found at [http://www.realscience.breckschool.org/upper/fruen/files/Enrichmentarticles/files/IronGallInk/IronGallInk.html About.com] While a very effective ink on vellum, the formula was less than ideal for paper, since the iron-tannin pigment would not make chemical bonds with the [[cellulose]] fibers. The ink still stuck firmly to the paper, but largely by mechanical bonding &mdash; namely the dried ink would penetrate the spaces between the fibers and, after drying would become entangled in them. Besides causing unsightly "ghost writing" on the obverse face of the paper, any excess of ferrous ions remaining in the ink, over years or decades, would create a rusty halo around the marks, and would ultimately cause the paper to disintegrate. == Demise == [[Image:Oak marble galls 1.JPG|thumb|left|<center>Oak marble galls, one with a Gall fly exit hole and another with Phoma gallorum fungal attack.]] The permanence and water-resistance of the iron and gall-nut formula made it the standard writing ink in Europe for over 700 years. Its use only started to decline in the 20th century, when other water-proof formulas (better suited for writing on paper) became available. Nowadays, iron gall ink is manufactured chiefly by artists enthusiastic about reviving old methods. == Warning == Iron gall ink is not suitable for [[fountain pen]]s as it will corrode them very quickly. Instead one should use modern surrogate formulas such as [[Montblanc (pens)|Montblanc]] blue-black, which has a very small amount of the ferro gallic compounds, or [[Rohrer & Klingner]] "Scabiosa" and "Salix" inks, both of which require the fountain pen to be flushed out regularly with water. == Alternatives == Recently alternative inks that bind with the [[cellulose]] in [[paper]], and which have neutral [[pH]], claim to offer superior waterproof, archival and fraud resistant qualities while being less dangerous to pens - e.g. [[Fountain pen inks#Noodler's|Noodler's]] 'Eternal' inks [http://www.moleskinerie.com/2005/01/noodlers_ink_th.html] [http://www.docradium.org/article.php?story=20050227012614337] [http://www.pendemonium.com/ink_noodler_info.htm] == See also == * [[Atramentum]] * [[Indian ink]] * [[Alizarine ink]] * [[Pen and ink]] * [[Ink]] - especially the section Writing Inks and Preservation * [[Oak Marble gall]] ==External links== *[http://www.knaw.nl/ecpa/ink/make_ink.html How to make iron gall ink], at an ink corrosion website. [[Category:Inks]] [[cs:Duběnkový inkoust]] [[de:Eisengallustinte]] [[it:Inchiostro ferrogallico]]