Research at the Institute for Restoration

In order to find the best preservation and storage methods, we carry out research projects on an ongoing basis together with partners. By analysing materials, we want to know why certain pigments or inks cause damage as they age. Examining paper, parchment, writing ink and painting materials helps us understand how artists worked in the past. We can determine the time a work dates back to and if all the parts are original.

Together with our partners, we test preservation methods and examine their effects on cellulose and parchment. We accelerate the ageing of samples: at high temperatures and air humidity or exposed to light. Everything we do should stand the test of time: the materials we use should continue to be stable in 100 years!

Green copper pigments on paper

Verdigris, a widely used green pigment on paper that contains copper, can turn brown as time passes. This results, for instance, in green meadows depicted losing their original colour. In addition to this, paper and parchment degrade and become brittle due to the copper ions.

Together with the Department of Chemistry at the University of Natural Resources and Life Sciences, we tested and examined various methods to stabilise verdigris pigments: mechanically with Japan paper and adhesives, and chemically with complexing agents and antioxidants. The project received funding from the forMuse programme of the Federal Ministry of Science and Research.

Using a copper complexing agent, the harmful effects of copper ions can be halted. We can stabilise paper made extremely brittle by verdigris using wafer-thin Japan papers with an adhesive layer, which we activate with a little moisture. We applied the findings of the project to the restoration of books of the Austrian National Library.

The results of our work have been published in the following magazines:

Kyujin Ahn, Christa Hofmann, Monika Horsky, Antje Potthast: How copper corrosion can be retarded – New ways investigating a chronic problem for cellulose in paper. In Carbohydrate Polymers 134 (2015): 136-143, doi:10.1016/j.carbpol.2015.07.040
Christa Hofmann, Andreas Hartl, Ina Faerber, Kyujin Ahn, Antje Potthast: Studies on the Stabilisation of Verdigris on Paper. In: Restaurator 2015, 36 (2): 147-182
Kyujin Ahn, Christa Hofmann, Andreas Hartl, Antje Potthast: Investigation of the stabilization of verdigris-containing rag paper by wet chemical treatments. In: Heritage Science 2014, 2:12, doi: 10.1186/2050-7445-2-12

You can find more information about our ongoing research project “Wiener Genesis” on our » research blog.