ブックタイトルConservation and Restoration of Western Paper

概要

Conservation and Restoration of Western Paper

binder. 1Although its use was widespread centurieslater, the oldest known recipe of an iron gallink has been found in the Greek PapyrusV of Leyden, dated around the 3rd century:“Myrrhe 1 Drachme, misy 4 drachmas,vitriol 4 drachmas, gallnuts 2 drachmas, gum3 drachmas.”2Since then, it is possible that ferroussulphate was added to common carbon inks,resulting in a better penetration and greaterpermanence of the ink in the support (firstparchment and later on paper), due to thesolubility of the salt, making the ink harderto remove. 3, 4Gradually, tannins fromvarious sources were added to the mixture,and since it was noticed that carbon was nolonger needed to obtain the black permanentcolor, it was slowly eliminated.Because of its permanence, iron gall inkwas particularly popular for legal documentsby the 11th century. 3, 5 By this period, paperalso enters Europe and the transitionfrom one ink to another could have beenaccelerated by the increasing demand forink, because of the new writing support. Bythe 14th century, iron gall ink was alreadyPhoto 3 Mexican oak gallsthe most used black writing ink in Westerncultures. 2In the 19th century, iron gall inks, likemany other products, started to be producedindustrially, and therefore their quality andpermanence was compromised. By the 20thcentury, synthetic dye inks gradually startedto replace iron gall ink, although it is stillcommonly found in documents from thefirst half of the 20th century.In Mexico, although the reaction betweentannins and iron salts for dyeing textiles wasknown before the 16th century, 6 it is likelythat iron gall inks arrived with the Spanishoccupation (1521), and that local ingredientswere gradually added, like the dye obtainedfrom logwood, which is mentioned inEuropean recipes of the 18th and 19thcenturies. 7Main components of iron gall inksThe main ingredients of iron gall inks are:vitriol (ferrous sulphate), tannins (gallicacid) and gum arabic, usually mixed inwater. Sometimes the water was replaced bybeer or wine to have fewer impurities, andmany additives were also used for differentpurposes.1.Vitirol: The word‘vitriol’was commonlyused to name salts with the appearance ofcrystals when dried. Ferrous sulphate is awater-soluble iron salt, with a slightly greencolor, so it was commonly referred as greenvitriol. It was very common that the saltshad impurities of other metals, dependingon the region where they were obtained.Iron sulphates used to contain impurities ofcopper, manganese, zinc and aluminum. 52.Tannins: Polyphenols with astringent46