| Abstract: | SUMMARY. Excellent co-operation between European partners with different expertise resulted in a range achievements: - Numerous iron gall ink recipes from the collected historical sources were evaluated and entered into the ICN Art Technological Sources database.4 - Ink corrosion database, a tool for visual assessment of numerous historical artefacts was created and will aid conservators in describing and documenting the documents. - Model rag papers were produced and their properties, such as pH, ageing stability, brightness stability during thermal ageing, metal content, etc, determined. They were used for evaluation of paper stabilisation treatments throughout the project. - Another study aimed at the evaluation of those factors, which result in the variable conditions of historical documents containing iron gall ink. Namely, while some are completely destroyed, others may be in excellent condition even centuries after their creation. In order to establish the main properties, common to severely degraded documents, (he effects of the type and quantity of transition metals in ink, as determined by in-air PIXE method, pH of the ink containing paper, grammagc of paper, its absorptivity and the width of ink lines were evaluated against the degree of corrosion. Using multiple linear regression analysis, a correlation has been obtained between the width of the applied ink lines, pH, grammagc of paper and the extent of ink corrosion. From these properties, which can be non-destructivcly obtained from most historical documents, it is therefore possible to predict the stability of historical iron gall ink containing paper.5 - Simple identification test for iron, developed by ICN, was evaluated and a novel one, aimed at identification of copper ions was developed, enabling conservators to identify the corrosive inks.6 - In-air PIXE method was used to determine the content of transition metals in 99 documents7. Iron content in ink containing paper reached values as high as 1656 mmol g -1 , while it did not exceed 38 mmol g -1 in areas, which did not contain iron gall ink. The results furthermore demonstrate that inks, containing substantial amounts of copper were used throughout the time span covered by our study.8 Molar ratio of copper to iron surpassed 10% in 32 manuscripts, while it was higher than 60% it 6 documents. Molar ratios of other potential catalysts9 were lower, not exceeding 5% for chromium, 6% for manganese and 10% for cobalt. - It was demonstrated that, under alkaline conditions, copper ions are much better catalysts of peroxide decomposition than iron ions.10-12 They may be the main source of damage exerted to numerous iron gall ink containing documents, once deacidification had been performed. Efficient antioxidants should therefore not focus on stabilisation of iron ions alone. - Evaluation of non-aqueous deacidification systems demonstrated that a solution deacidification is preferred over a suspension system. Research within InkCor project led to several improvements of the existing commercial process for mass deacidification of books, which have been already implemented by the SME partner, Zentrum fuer Buchcrchaltung (ZfB). The quality of deacidification agent magnesium titanium ethoxide was improved, resulting in diminished yellowing of treated papers. Conditioning room was built to allow for faster conversion of deacidification agent into the corresponding carbonates. - In order to develop a non-aqueous method for stabilisation of iron gall ink containing paper, a number of antioxidants was evaluated. The most promising turn out to be a group of peroxide decomposers, which arc able to inhibit oxidative decay irrespectively of the type of transition metal which catalyses it. Results demonstrate that while deacidification using magnesium ethoxidc in ethanol (0.05 mol L-1) decreased degradation of iron gall ink containing paper by 50 +- l0%, treatment with a non-aqueous InkCor process resulted in 80 +- 10% slower degradation (Figure 1), as compared to the untreated paper. In addition to stabilising paper containing iron gall inks, new process inhibits degradation of the paper itself (without iron gall ink) in alkaline environment,8 thus offering additional benefits of the proposed potential stabilisation method. As a result of the research undertaken within the project ZfB, National and University Library of Slovenia and University of Ljubljana, Slovenia jointly submitted a patent for a new non-aqueous paper stabilisation method containing antioxidants. After three years of research, the project will draw to a close in February 2005. Until then, the novel treatment for papers containing corrosive iron gall inks will be extensively evaluated by the researchers and end-users in the project, in order to determine whether it can be safely used for stabilisation of historical artefacts. |
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