Wilfried Vetter

Dr. Wilfried Vetter


Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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3 April 2019 in Heritage Science
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Journal Article
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WVWilfried Vetter
Wilfried Vetter
ILIrene Latini
Irene Latini
MSManfred R. Schreiner
Manfred R. Schreiner
In illuminated manuscripts, a reliable identification of oxyanion pigments such as azurite by rFTIR is simple, as several combination and overtone bands are strongly enhanced compared to transmission mode. However, the characterization of the used binding media is rather difficult, as the analysis of four medieval manuscripts from the late thirteenth to the fifteenth century (e.g. Cod. slav. 8 in the collection of the Austrian National Library), as well as the earliest known map of Vienna (Albertinischer Plan from 1421, Wien Museum) showed. According to the literature, mainly glair (egg white) and plant gums were applied as binding media for azurite. Moreover, both were used in many cases also as “varnishes” in order to improve optical and mechanical properties of the paint layer. In order to assess the possibilities and to distinguish between proteinaceous and carbohydrate binders, mock-ups with azurite were prepared on parchment support with various quantities of binders. Additionally, some of the specimen were varnished using the binders mentioned above. Furthermore, mock-ups on aluminium foil were prepared to evaluate the influence of the support on the reflection spectra. The results showed that the binding medium content in the mock-ups usually was too low for a reliable determination by rFTIR (except the ones with the highest contents), whereas it was possible to characterize the varnish materials. Only an insignificant influence of the support on the spectra from the mock-ups was observed. However, the spectra obtained from three manuscripts suggested a certain influence of the parchment support, which indicates thinner paint layers.

23 July 2021 in Heritage Science
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Journal Article
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WVWilfried Vetter
Wilfried Vetter
BFBernadette Frühmann
Bernadette Frühmann
FCFederica Cappa
Federica Cappa
MSManfred R. Schreiner
Manfred R. Schreiner
A multianalytical approach was used to characterize the materials in the “Vienna Moamin”, an outstanding richly illustrated manuscript from the late thirteenth century, which was made in Italy and is now kept in the Kunsthistorisches Museum Wien. The investigations were carried out with a non-invasive approach by using complementary techniques, such as X-ray fluorescence (XRF), reflection Fourier transform infrared spectroscopy (rFTIR), Raman spectroscopy, and fiber optic reflectance spectroscopy (FORS). In addition, XRF scans were performed in two areas which yielded chemical maps showing the elemental distribution. The results revealed that typical materials from the medieval times were applied for the manuscript. Calcium carbonate on the parchment surface indicated a dehairing process with lime and/or whitening with chalk. Two different iron gall inks were detected in the main text and marginal notes, and vermilion was used for rubrication. The color palette included azurite, a green colorant composed of orpiment and indigo, yellow ochre, brown iron oxide pigments, minium, vermilion, brazilwood lake, and carbon black. Moreover, mosaic gold was detected in gold-beige hues. Lead white was identified for white areas and fine decoration lines, as well as in mixture with blue and red pigments for light color shades. No reliable information could be obtained concerning the binding media. Two differing application techniques for gold leaf were detected, which correspond with stylistic differences: either on gypsum or chalk preparation layers. Furthermore, calcium soap contents in certain colors were determined only on one folio with unique characteristics. The XRF scans of two historiated initials revealed that similar materials were applied in both cases and provided further valuable information about the painting technique. The results obtained enabled to gain insights into Italian thirteenth century manuscript production techniques and to characterize the used materials. The investigations showed the importance of scanning XRF for the elucidation of painting techniques, but also the demand of scanning devices utilizing compound specific analytical techniques such as rFTIR.

17 October 2022 in Applied Sciences
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GPGuadalupe Pinar
Guadalupe Pinar
FCFederica Cappa
Federica Cappa
WVWilfried Vetter
Wilfried Vetter
MSManfred R. Schreiner
Manfred R. Schreiner
HMHeinz Miklas
Heinz Miklas
KSKatja Sterflinger
Katja Sterflinger
This article reviews the complementary strategies that are used to decipher the valuable information that is contained in ancient parchment documentary materials. A new trend is molecular analysis, which has given rise to the emerging field of biocodicology, comprising protein and DNA analysis for the identification of the biological origin of the skins that are used for their manufacture. In addition, DNA analysis can identify the microbiome that is present in the object under investigation, which adds value by providing information on its history and state of preservation. In any case, it is important to complement the biomolecular investigations with microscopical and physicochemical analyses. Some of the complementary analytical techniques that are reviewed here, such as elemental analysis by X-ray fluorescence (XRF) with compound-specific analytical methods such as Fourier transform infrared (FTIR) and Raman spectroscopy are advantageous as they can be applied in a non-invasive way and without inducing any changes in the objects.

14 June 2021 in Polymers
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VPValentina Pintus Pintus
Valentina Pintus Pintus
APAnna Piccolo
Anna Piccolo
WVWilfried Vetter
Wilfried Vetter
Ligia Maria MorettoLigia Maria Moretto
Ligia Maria Moretto
KSKatja Sterflinger
Katja Sterflinger
MSManfred R. Schreiner
Manfred R. Schreiner
The ageing behavior of phenol formaldehyde (PF) foam, a material increasingly used in modern-contemporary art, was investigated by a multi-analytical approach. PF foams with open- and closed-cell structures were selected and analyzed in their unaged and naturally indoor-aged state by employing optical microscopy (OM) and fiber optical reflectance spectroscopy (FORS) for assessing their morphology and color alteration. Micro-Fourier transform infrared spectroscopy (μ-FTIR) was used for determining chemical changes and oxidation processes, and the acidity was monitored by pH measurements. The results clearly showed the extreme sensitivity of both open- and closed-cell PF foams to conditions typically found in indoor museums. OM indicated that the cells of the foams are prone to disrupt, and a tendency towards a red color shift was observed with FORS. μ-FTIR revealed the formation of quinone groups resulting from oxidation reactions. Finally, a slight decrease in the acidity was found by pH measurements.

17 October 2024 in Biomimetics
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MZMarkus Zimmerl
Markus Zimmerl
Richard Wilhelm van NieuwenhovenRichard Wilhelm van Nieuwenhoven
Richard Wilhelm van Nieuwenhoven
KWKarin Whitmore
Karin Whitmore
WVWilfried Vetter
Wilfried Vetter
Ille C. GebeshuberIlle C. Gebeshuber
Ille C. Gebeshuber
The increasing occurrence of hot summer days causes stress to both humans and animals, particularly in urban areas where temperatures can remain high, even at night. Living nature offers potential solutions that require minimal energy and material costs. For instance, the Saharan silver ant (Cataglyphis bombycina) can endure the desert heat by means of passive radiative cooling induced by its triangular hairs. The objective of this study is to transfer the passive radiative cooling properties of the micro- and nanostructured chitin hairs of the silver ant body to technically usable, biodegradable and bio-based materials. The potential large-scale transfer of radiative cooling properties, for example, onto building exteriors such as house facades, could decrease the need for conventional cooling and, therefore, lower the energy demand. Chitosan, a chemically altered form of chitin, has a range of medical uses but can also be processed into a paper-like film. The procedure consists of dissolving chitosan in diluted acetic acid and uniformly distributing it on a flat surface. A functional structure can then be imprinted onto this film while it is drying. This study reports the successful transfer of the microstructure-based structural colors of a compact disc (CD) onto the film. Similarly, a polyvinyl siloxane imprint of the silver ant body shall make it possible to transfer cooling functionality to technically relevant surfaces. FTIR spectroscopy measurements of the reflectance of flat and structured chitosan films allow for a qualitative assessment of the infrared emissivity. A minor decrease in reflectance in a relevant wavelength range gives an indication that it is feasible to increase the emissivity and, therefore, decrease the surface temperature purely through surface-induced functionalities.

1 January 2017 in ChemViews
Verified
Journal Article
Closed access
MSManfred Schreiner
Manfred Schreiner
RWRita Wiesinger
Rita Wiesinger
WVWilfried Vetter
Wilfried Vetter