Cover Image

Enzymes in Solvent Conditioned Poultices for the Removal of Starch-based Adhesives from Iron Gall Ink Corroded Manuscripts

Bibliographic Details
Main Authors:	Schönbohm, Dirk (Author), CONCLUSION. In principle, it is possible to use semi-aqueous amylase poultices for breaking down starch adhesives. However, the organic solvent incorporated into the poultice to prevent the migration of water-soluble iron gall ink degradation products, also reduces the reactivity of the enzyme. In this study, it was found that in order to protect iron gall ink inscriptions effectively, the organic solvent percentage had to be increased above 3.5% (v/v). At higher organic solvent concentration, enzyme activity was reduced. The migration of ink degradation products could only be prevented when the artifact to be poulticed was first impregnated with a semi-aqueous solution diluted with at least 35% ethylene glycol monomethylether (EGMM). To dissolve modified starch adhesives treated with an agent preventing its swelling, concentrations of 35-80% EGMM were needed. The higher the organic solvent concentration, the lower was the risk of ink migration, but at the same time, the treatment required to achieve the dissolution of the starch had to be prolonged. The prolonged treatment time, in turn, increased the risk of ink migration. The thickness of the starch layer also affects the treatment time. In our study, we found that modified starch adhesive could be released in less than 32 minutes This research into semi-aqueous enzyme poultices resulted in the development of a treatment method that was effective in releasing undesirable adhesives in one conservation treatment case. The study also presents a systematic approach by which conservators can weigh risk against benefit of this type of treatment. The treatment methods presented in this study, however, should not be considered a treatment recipe (Author), Blüher, Agnes (Author), Banik, Gerhard (Author)
Format:	Article
Language:	English Slovak
Online Access:	http://www.viks.sk/chk/res_4_04_267_281doc

Description
Abstract:	SUMMARY. Semi-aqueous amylase poulticing methods were tested with the objective to detach silking from archival documents weakened by iron gall ink corrosion. Originally amylose gels on the basis of methylcellulose as gel forming agent containing methyl cellosolve were used to remove wheat starch paste adhesives modified by addition of aluminiumsulfate from test artifacts that have been restrenthened according to the traditional siliking technique. These experiments led to the development of polyethylenoxide gels in which the methyl cellosolve and amylase were incorporated. A system was developed by which a fully aqueous amylase gel was used to detach silking from iron gall ink test artifacts protected from the contact with water by having been impregnated with ethylene glycol monomethylether (EGMM) - water blends. The migration of ink and degradation products could successfully be prevented when the artifact to be poulticed was firstly impregnated with the organic solvent. The method was sucessfully used on original artifacts.
ISSN:	0034-5806