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Publications (50)
During the process of conserving the painting La Salle des Cariatides au Louvre
(1921) by Edouard Vuillard at the Atelier Eysler GmbH, damage was discovered
in the form of stiff, fragile, and slightly lifted paint flakes. The heavily concave
painting layer could not be flexed either with moisture or heat. The surface of the
painting appeared dull,...
This paper explores the foaming of methylcellulose (MC) using straightforward foaming and drying methods for different applications in the field of conservation and restoration. The aim was to elaborate a low-tech, inexpensive and reproducible foaming method to achieve dimensionally stable, homogeneous, dried foams. Crucial influencing parameters o...
Between 1924 and 1947, Gino Severini decorated five churches in the Romand region of Switzerland with monumental religious wall paintings. This mural art played an important role in the Italian artist's career despite being mostly unknown and not easily found. The painting methods and materials of these modern Swiss murals were characterized by com...
The increasing demand for functional materials and an efficient use of sustainable resources makes the search for new material systems an ever growing endeavor. With this respect, architected (meta‐)materials attract considerable interest. Their fabrication at the micro‐ and nanoscale, however, remains a challenge, especially for composites with hi...
Adhesive meshes are micro-structured and honeycomb-shaped, flexible adhesive nets. They can be produced from a variety of adhesives such as water-soluble methylcelluloses or sturgeon glue. These two have proofed long-term stability for several decades now and have found wide application in the field of conservation. If a painting allows for tempora...
In heritage sciences, the ability to obtain information about the origin and dating of cultural heritage objects is fundamental for placing an object into its historical context. Radiocarbon (14C) dating can help to identify the period during which a work of art was created by dating its constitutive materials. Such information can, however, only b...
It is no secret and yet not all pilgrims know that the “black Ma- donna” from the Einsiedeln monastery in central Switzerland, dated in the 15th century, originally had a white incarnate and was painted over in black in 1799. According to a very early documentation, the reason given was the optical regression to the rusty appearance. This colour ch...
Cultural heritage built from limestone is prone to deterioration by chemical weathering , a natural process, that is enhanced by pollution. There are many historic monuments built from calcareous rocks that suffer from deterioration, and thus there have been a number of approaches over the last few decades to consolidate these types of rocks and su...
Lead white is known as one of the oldest pigments in art and can be used as a dating material. Upon production following the Stack process, the ¹⁴C isotope of atmospheric carbon dioxide is fixed in the carbonate, and its radiocarbon dating can be used as a proxy for the age of a painting. The previously reported carbonate hydrolysis protocol reache...
Augusto Giacometti’s painting The Circling of the Planets (1907; 268 × 218 cm) is in a highly fragile state, suffering from widespread flaking paint. These flakes are very brittle and rigid; none of the usual consolidation techniques managed to achieve necessary ductility to secure lifting paint flakes. In the blue areas, both absorbent protein-oil...
Significance
Can radiocarbon ( ¹⁴ C) dating uncover modern forgeries? Radiocarbon dating has the potential to answer the question of when an artwork was created, by providing a time frame of the material used. In this study we show that with two microsamples (<500 μg), from both the canvas and the paint layer itself, a modern forgery could be ident...
Synthetic organic pigments (SOPs) have been widely applied in modern and contemporary painting and are used extensively in conservation-restoration practice. Nevertheless, while SOPs have already 150 years of history, in which hundreds of different SOPs have been synthesized, these pigments are understudied in comparison to the more classic ranges...
Augusto Giacometti’s painting The Circling of the Planets (1907; 268 × 218 cm) is in a highly fragile state, suffering from widespread flaking paint. These flakes are very brittle and rigid; none of the usual consolidation techniques managed to achieve necessary ductility to secure lifting paint flakes. In the blue areas, both absorbent protein-oil...
Zwischgold (also part-gold in English) is a two-layered metal foil made of gold and silver that was historically applied to altarpieces, sculptures and panel paintings. It tends to oxidize quickly in air and therefore was usually applied with a protective varnish layer. The purpose of applying Zwischgold is an interesting topic in the research of a...
Lead white is a man-made white pigment commonly used in works of art. In this study, the possibility of radiocarbon dating lead white pigments alone and in oil paints was explored using well-dated lead white pigments and paints. Resulting ¹⁴ C ages on lead white pigments produced following the traditional stack process, where carbonate groups resul...
Modern oil paints are often optimized by the artist himself in the course of experiments.
Unfortunately, the outcome is not always as expected by the artist. In the case of Augusto Giacometti's „The Circling of the Planets" (in german: "Das Kreisen der Planeten“) from 1907, for example, the artist had to struggle with the degradation phenomena flak...
Zwischgold is a two-sided metal foil made by adhering a gold leaf over a silver leaf to present a gold surface while using less gold than gold foils. Corroded Zwischgold surfaces appear dark, accompanied by gloss loss and possible mechanical stability issues. Zwischgold applied artefacts are commonly found in museums and churches across Europe and...
The use of accelerator mass spectrometry (AMS) for age determinations of paintings is growing due to decreasing sample size requirements. However, as only the support material is usually dated, the validity of the results may be questioned. This work describes a novel sampling and preparation technique for dating the natural organic binder using ra...
A specific case of degradation was observed in synthetic ultramarine paint within 3 paintings from the early 20th century, manifesting as an intricate pattern of white lines criss-crossing the blue paint surface. Raman spectroscopy can be performed directly on untreated sample surfaces and is sensitive to the colour components in ultramarine (S3⁻ a...
A number of ultramarine paint samples were analysed by Raman spectroscopy and X-ray photoelectron spectroscopy to determine the binding energies of the S3.- (blue) and S2.- (yellow) radical anions responsible for the pigment colour. The two sulphur radicals (chromophores) have well assigned Raman signals, however, no previous XPS study has been abl...
Infrared spectroscopy (FTIR) is a standard technique for the characterisation of organic materials in conservation science. This analytical technique is particularly interesting to analyse historical varnishes from cultural artefacts, as only minute samples are required. Some limitations apply, however, when analysing such chemically complex multi-...
Analysis of bioorganic materials by infrared spectroscopy (FTIR) is frequently limited due to overlapping of diagnostic bands from the various components, which poses a fundamental problem to this analytical technique. The distinction of oxidised di- and triterpenes, for example, is hindered by the superposition of similar absorption bands of carbo...
In this paper, radiocarbon dating of paintings using minimal sample sizes has been investigated, in an effort to address the problem of limited access to sample material in paintings. 14C analyses were conducted on signed and dated paintings from two Swiss artists of the twentieth century. The selected paintings dated from the 1930s and 1960s, prov...
During the examination of two 19th century oil paintings by Swiss artists, the Reading pastor (ca. 1885) by Ferdinand Hodler (1853–1918) and Portrait of a young girl (ca. 1888) by Filippo Franzoni (1857–1911), it was observed that in particular locations, the surface had an unusually granular texture, given by the application of metallic particles...
The kinetics of dissolution and rates of leaching were studied in relation to the surface cleaning of modern oil paint in art conservation. A wide range of materials of different polarity and molecular mass was tested to characterise the rate of dissolution. The large data set suggests that the rate of solvent action is mainly influenced by the phy...
Synthetic organic pigments ale widely used in contempolaly artistsand
house paints. They can be fbund in artworks since 1900. Because of their
special particle properties and their solubility in solvents, however, synthetic organic
pigments pose a special challenge in conservation treatments. Analyses have been
carried out on 23 synthetic olganic p...
The interpretation of standard Fourier transform infrared spectra (FT-IR) on oil-based paint samples often suffers from interfering bands of the different compounds, namely, binder, oxidative aging products, carboxylates formed during aging, and several pigments and fillers. The distinction of the aging products such as ketone and carboxylic acid f...
Synthetic organic pigments are widely used in contemporary artists- and house paints. They can be found in artworks since 1900. Because of their special particle properties and their solubility in solvents, however, synthetic organic pigments pose a special challenge in conservation treatments. Analyses have been carried out on 23 synthetic organic...
In conservation science the Fourier transformed based infrared spectroscopy (FTIR) is a standard technique to the study of historic paint layers. There are, however, clear limitations when analysing modern oil paint. The spectral information of aged oils is affected from overlapping signals of the binder, the oxidative ageing products, soaps formed...
Abstract Phthalocyanine pigments are commonly used in artist’s paints [PG7 (1936), PG36 (1957), PB15 (1928), PB16 (1939)], can easily be detected by Raman spectroscopy and are thus of interest for authentication purposes. Apart from PG36 and PB16, they all give a good response with the 785nm laser, which seems the most versatile wavelength for pigm...
Cleaning strategies in restoration and conservation often involve the use of solvent mixtures, despite the fact that the interaction between these and the objects under treatment is not always well known. Binary solvent mixtures behave nonideally; that is, the properties are not directly proportional or related to the mixing ratio. This fact contra...
Some 170 organic pigments relevant to artist's paints have been collected from historic collections and modern manufacturers. The number includes multiples of the same pigment from different sources and comprises 118 different color indices (C.I.). All of them have been analysed with FTIR spectroscopy and 125 pigments (93 different C.I. No.s) of pa...
Synchrotron based X-ray microtomography is a novel way to examine paint samples. The three dimensional distribution of pigment particles, binding media and their deterioration products as well as other features such as voids, are made visible in their original context through a computing environment without the need of physical sectioning. This avo...
Pigment analyses on more than 90 paintings dating from between 1885 and 1943 (A. Jawlensky, W. Kandinsky, F. Hodler and C. Amiet) have revealed that the majority of samples with chromium oxide hydrate green contain a spectroscopically conspicuous by-product. With the aim of tracking down the origin of this component, the so-called Guignet green, a...
A Békési-medence északi peremén fúrásokkal jól feltárt aljzat blokkok kőzetanyaga lehetőséget ad a terület metamorf fejlődéstörténetének rekonstrukciójára. Ez a nyomás-hőmérséklet-deformáció (P–T–d) evolúció vizsgálata mellett a geokronológiai viszonyok elemzését jelenti. Munkánkban korábbi geokronológiai adatok, valamint új K/Ar (amfibol, földpát,...
The integration of information which can be gained from accessory [i.e. age (t)] and rock-forming minerals [i.e. temperature (T) and pressure (P)] requires a more profound understanding of the equilibration kinetics during metamorphic processes. This paper presents an approach comparing conventional P–T estimate from equilibrated assemblages of roc...
A newly developed XRF-microprobe at the Institute of Mineralogy and Petrology, University of Bern, Switzerland has been applied for precise chemical Th–U–Pb dating of individual monazite grains separated from Pb-free polished petrographic thin sections. The nondestructive nature of the XRF-measurement permitted a comparative study of dating methods...
Despite the recognised importance of monazite in geochronology, the contextural information is lost when using standard mineral separation techniques. To overcome this problem, new techniques were developped to date monazite in thin section or as grains drilled out from thin sections.
Chemical Th-U-Pb dating of monazite on the microprobe is limit...
A suite of metapelites from the pre-granitic basement of the Monte Rosa nappe was collected and investigated to gain insight into the evolution of this important upper Penninic thrust sheet. Careful sampling at mesoscopic to microscopic scale allowed the identification of relics of distinctly pre-Alpine origin, of assemblages formed in the early Al...
Bearthite, Ca2Al[PO4]2(OH), an aluminum phosphate that may contain up to ∼ 10 wt% of light rare-earth elements (LREE) + Th, shows various breakdown textures in high-pressure metamorphic rocks. Two such reactions are described: (1) a pyrope-bearing kyanite-phengite-quartz (coesite) schist from the high-pressure Dora-Maira terrane, Italy, in which be...
Despite the recongnized importance of monazite in geochronology and petrology, a range of fundamental analytical and preparational problems remains. For example, chemical Th-U-Pb dating of monazite requires special lead-free sample preparation. This is achieved efficiently and at high quality with specially developped grooved ND-PE polyethylene pol...
