Christa Hofmann, IfR
Andreas Hartl, IfR
Ahn Kyujin, University of Natural Resources and Life Sciences, Department of Chemistry
Antje Potthast, Ute Henniges, University of Natural Resources and Life Sciences, Department of Chemistry
Erna Pilch-Karrer, Austrian State Archive
Dianne van der Reyden, Eric Hansen, Library of Congress, Directorate of Preservation
Program forMuse – Research at museums, Federal Ministery of Science and Research
Copper green corrosion on illuminated manuscripts, coloured prints and maps
In the framework of the program forMuse the Austrian Minstry of Science and Research funds a project of the Austrian National Library in cooperation with the University of Natural Resources and Life Sciences (BOKU). The focus of the project is the degradative action of copper green pigments on paper and treatment options in conservation. Copper green pigments or verdigris have been used for coloured images in manuscripts, prints and maps from the Middle Ages to the 19th century. Copper green pigments can discolour and become brown. Copper green ions could be responsible for the degradation of cellulose which results in severe mechanical damage. The paper becomes increasingly brittle.
In the conservation department preventive measures and treatment options are tested on model papers with copper green pigments. In the chemistry department of BOKU the paper samples and the effect of different treatments are analysed before and after artificial ageing on a molecular level. Among the treatments tested range the mechanical stabilisation with Japanese papers and a variety of adhesives as well as the chemical stabilisation by alkaline solutions, complexing agents and antioxidants. The aim of the project is to gain deeper understanding of the degradation processes and to provide conservators with information and tools for the preservation of copper green pigments.