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Stuttgart Muhlhausen, Germany

Banik G.,University of Applied Arts Vienna | Bruckle I.,Stuttgart State Academy of Art and Design
Restaurator | Year: 2010

The unique attributes of water are discussed, focusing on its physical interaction forces that operate and between water molecules and other materials to which it can establish a close contact, such as cellulose or paper. Selected scientific principles of the water interactions relevant to water damage focusing on water absorption of cellulose are highlighted, followed by selected drying strategies for cellulosic materials discussed for their mechanisms and side effects. The contribution is an excerpt of the textbook Water in Paper: A Guide for Conservators (Elsevier, Butterworth-Heinemann, in print). © De Gruyter Saur 2010.

Hummert E.,Stuttgart State Academy of Art and Design | Henniges U.,Christian Doppler Laboratory | Potthast A.,Christian Doppler Laboratory
Cellulose | Year: 2013

For the conservation of artworks on paper, powdery paint layers on the paper matrix are stabilized with dilute solutions of adhesives (0.25-1 %), commonly gelatin or methylcellulose, which are applied as aerosols. This technique allows non-contact application. The distribution of the adhesives must be carefully controlled: they have to be delivered to unstable paint layers in the right quantity to avoid visual alterations of the artwork during the stabilization treatment. To visualize the distribution of aerosol-misted adhesives in porous substrates, gelatin and methylcellulose were labeled with fluorescent dyes, purified from excess label, and applied on sample specimen featuring powdery pigment layers on handmade rag paper. As blank comparisons, sample papers without pigment layers were included to verify whether aerosol-misted adhesives are a suitable method to stabilize fragile papers. Penetration of the adhesive-label-conjugates was observed at thin sections of the samples by fluorescence microscopy. The fluorescence labeling of gelatin with Texas Red™ allowed an excellent visualization of aerosol-misted adhesive (0.5-1 %) in all sample types. Methylcellulose (Methocel™ A4C) labeled with Texas Red™ C2-dichlorotriazine enabled fluorescence tracing if applied in 0.5 % solutions by immersion. Aerosol application permitted local adhesive application, making it a suitable technique for stabilizing fragile papers. If applied to samples with low porosity, aerosol-misted gelatin was mainly deposited at the surface, whereas in porous filter paper, penetration dominated over surface deposition. Intermediate drying between repetitive applications apparently limited the penetration of aerosol-misted gelatin. © 2013 Springer Science+Business Media Dordrecht.

Schonemann A.,Stuttgart State Academy of Art and Design | Edwards H.G.M.,University of Bradford
Analytical and Bioanalytical Chemistry | Year: 2011

Tung oil is favoured in applications such as historic wood consolidation or as varnish component that require a rapid-drying medium compared with linseed oil and other analogues such as walnut oil and poppy seed oil. The Raman spectra of tung oil and artificially aged specimens have been obtained and indicate that severe degradation of the C=C unsaturation sites occurs compared with the slower-drying linseed oil. Characteristic spectral signatures of fresh tung oil have been identified which provide diagnostic discrimination between this oil and others used in the preparation and preservation of artworks. Mid-infrared spectra of aged tung oils have served to identify the formation of acidic functionalities which could affect associated pigments and substrates in artwork. Comparative spectra are also reported for a range of other oils such as walnut seed, poppy and sunflower seed oils. © 2011 Springer-Verlag.

Pataki A.,Stuttgart State Academy of Art and Design | Potthast A.,University of Vienna | Bruckle I.,Stuttgart State Academy of Art and Design
Restaurator | Year: 2015

The ionic fixatives Rewin® EL and Mesitol® NBS are in established use to prevent bleeding of water-sensitive media during aqueous treatment. Their single or combined application varies among practitioners, also with regard to the inclusion and intensity of any subsequent rinsing. Lack of rinsing and local fixative applications are known to risk paper discolouration. The function of aqueous rinsing subsequent to fixative application was studied on Whatman filter paper samples treated with fixative solutions of Mesitol® NBS, Rewin® EL or the Bückeburg fixative solution, which is a suspension of both. After artificial ageing, the samples were analysed as follows: discolouration formation via CIELAB measurement; cellulose damage via molar mass (Mw) and carbonyl group content; alteration of the paper's electrostatic charge via dye colouration; quantification of fixative residues via gravimetry, polyelectrolyte extraction and IR spectroscopy. Results on treated and artificially aged papers show that rinsing is of great importance for diminishing the residue and thereby any negative effect of remaining fixatives discolouration formation, Mw loss and carbonyl group increase. Papers treated with Rewin® EL and the Rewin® EL-containing Bückeburg fixative solution showed these effects significantly. Mesitol® NBS seemed to have no negative, and may have a positive effect on the studied paper ageing properties. One 15-min aqueous rinse was the minimum required, three 10-min rinses were effective in maximising the fixative removal from Whatman filter paper, which is crucial to prevent undesired side effects. © 2015 by De Gruyter.

Echard J.-P.,Laboratoire Of Recherche Et Of Restauration | Echard J.-P.,French National Center for Scientific Research | Bertrand L.,Synchrotron Soleil | Von Bohlen A.,Leibniz Institute for Analytical Sciences | And 9 more authors.
Angewandte Chemie - International Edition | Year: 2010

Figure Presented What is Stradivari's "secret"? The composition of the mythical varnish that coats Stradivari's violins has raised controversial assumptions for the past two centuries. By using a complementary array of analytical tools, the chemical microstratigraphy of these varnishes has been established. The results provide information on the materials and techniques that were used by the Master, with a detailed characterization of the varnish chemical equation presentation © 2010 Wiley-VCH Verlag GmbH &. Co. KGaA, Weinheim.

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