Papers by Joosje Van Bennekom
Electrochimica Acta, 2020
This report proposes a refined method to date archaeological gold samples based on the Tafel anal... more This report proposes a refined method to date archaeological gold samples based on the Tafel analysis of the ascending part of voltammetric curves corresponding to the oxidation of surface flakes of gold in contact with hydrochloric acid aqueous electrolyte. This allows estimating the equilibrium potential of gold oxidation correcting for irreversibility effects. This equilibrium potential can be correlated with the coverage of adsorbed oxygen species and hence the estimated age of the gold samples. A satisfactory potential/time calibration graph was constructed from a set of archaeological samples including two sets of samples from the Mapungubwe Gold Collection, South Africa (1200e1290 CE) and Santa Llúcia, Alcal a de Xivert in Spain (dated back 600-550 BCE) sites. The dated samples come not only from different continents, but their ages also cover more than 3000 years.
Tarnished silver objects contain a black layer of silver sulfide. Current cleaning methods are no... more Tarnished silver objects contain a black layer of silver sulfide. Current cleaning methods are not suitable for fragile objects, therefore, this exploratory study set out to develop a new biology-based method to clean silver. The extremophile bacterium Acidithiobacillus ferrooxidans was considered the most promising candidate, because of its ability to oxidize metal sulfides. The bacterium indirectly removed silver sulfide from tarnished silver coupons, through the generation of ferric iron. However, this procedure etched the silver. It was investigated whether A. ferrooxidans was able to directly oxidize silver sulfide in the absence of iron. However, no removal of silver sulfide was observed.
Journal of Archaeological Science: Reports
When examining the alloy of several works of Adam van Vianen, who was one of the founders of the ... more When examining the alloy of several works of Adam van Vianen, who was one of the founders of the Dutch Kwabstijl, with X-ray fluorescence, a much higher silver and lower bismuth percentage and was found in the silver than was commonly used by his contemporaries. It is the hypothesis that Van Vianen used a high percentage of silver, as it is more malleable, and he could therefore obtain extreme deformation of the silver without the formation of cracks. Recipes on silver production and refinement in the silversmith workshop that would have been commonly used at the time were selected to serve as a basis for making reconstructions in silver. These books were-the Probierbuchlein by Calbus of Freiberg and the Description of Leading Ore Processing and Mining Methods by Lazarus Ercker. Reconstructions were made, and the 'test' procedure, leading to 'blick' silver, generated highly refined silver, the silver being very malleable. It is therefore concluded that this recipe could have been used on purpose by Adam van Vianen to make his elaborate objects. On the other hand, there exists the possibility that this low bismuth content might be generated by coincidence, as a side effect to the multiple annealing and pickling cycles the objects went through.
The so-called 'Merkelsche Tafelaufsatz', a centrepiece made by the Nuremberg goldsmith We... more The so-called 'Merkelsche Tafelaufsatz', a centrepiece made by the Nuremberg goldsmith Wenzel Jamnitzer in 1549, is one of the most famous masterpieces in goldsmithing from the sixteenth century. For the opening of the new Rijksmuseum, the centrepiece needed conservation treatment, which provided the opportunity for an in-depth examination. One of the most interesting findings concerned the so far undiscovered remnants of a largely removed etched text on the silver plaque fixed to the bottom of the piece. The traces of the text, which must derive from the time Jamnitzer made the centrepiece, were non-destructively analysed with the AGLAE mapping system at the Musée du Louvre, and some letters could be discriminated. These results shed new light on the history of the piece and a possible special occasion for which this object may have been made.
ICOM-CC 18th Triennial Conference Metals, 2017
A famous 16th-century masterpiece, a large centrepiece by goldsmith Wenzel Jamnitzer, was treated... more A famous 16th-century masterpiece, a large centrepiece by goldsmith Wenzel Jamnitzer, was treated for the New Rijksmuseum. This object is known for its life casts, real plants and animals cast in silver. These life casts were tarnished and some were broken. Research compared different cleaning techniques for tarnished, fragile silver. Tests indicated that local electrolytic cleaning with refreshed electrolytes-a new technique-would be the most appropriate method, but this approach did not work on the object itself, probably because of an impermeable layer present on the life casts. In the end, the life casts were not cleaned completely. Instead, the decision was made to wait until the electrolytic or plasma method has been perfected and tuned for these life casts. Broken life casts were joined by a new method utilising inert transparent shrinking tubes. Conservation of the 16th-century Merkelsche Tafelaufsatz created by the German goldsmith Wenzel Jamnitzer
A famous 16th-century masterpiece, a large centrepiece by goldsmith Wenzel Jamnitzer, was treated... more A famous 16th-century masterpiece, a large centrepiece by goldsmith Wenzel Jamnitzer, was treated for the New Rijksmuseum. This object is known for its life casts, real plants and animals cast in silver. These life casts were tarnished and some were broken. Research compared different cleaning techniques for tarnished, fragile silver. Tests indicated that local electrolytic cleaning with refreshed electrolytes-a new technique-would be the most appropriate method, but this approach did not work on the object itself, probably because of an impermeable layer present on the life casts. In the end, the life casts were not cleaned completely. Instead, the decision was made to wait until the electrolytic or plasma method has been perfected and tuned for these life casts. Broken life casts were joined by a new method utilising inert transparent shrinking tubes. Conservation of the 16th-century Merkelsche Tafelaufsatz created by the German goldsmith Wenzel Jamnitzer
The Rijksmuseum Bulletin, 2019
The imposing Chola-period bronze Shiva Nataraja at the Rijksmuseum is a product
of the living tr... more The imposing Chola-period bronze Shiva Nataraja at the Rijksmuseum is a product
of the living tradition of metal casting established over a thousand years ago in
the region of Tamil Nadu. Purchased in 1935 from a Parisian dealer, it is one of the
highlights of the collection belonging to the Royal Asian Art Society in the Netherlands, which is exhibited at the Rijksmuseum. The interdisciplinary study presented
here links an art historical investigation of ancient texts and scholarly literature with
scientific analysis in an attempt to refine the art historical context and at the same
time flesh out what is known about the fabrication and provenance of the Nataraja
in the Rijksmuseum. The Nataraja was cast by the lost-wax method; x-ray images
confirm that the Shiva is solid-cast together with the halo. X-ray fluorescence
reveals an alloy consistent with other Chola-period bronzes but not necessarily a
pañcaloha alloy (five metals), which seems to be a modern tradition; the front hands
were apparently cast on separately as a repair, probably during casting or not long
after. Further evidence gathered from the sculpture and its soil encrustations (icp-ms
lead and neodymium isotope ratios, sem-edx and xrd) is briefly presented, and
supports earlier assumptions about the Nataraja. It appears to date from the twelfth
century and was under worship for a relatively short time before it was buried at
an unknown location in India. The presence of Indian earth and corrosion products
typical of burial imply that it did not re-enter a temple context for worship and
was not subject to major restoration before entering the art market in the early
twentieth century
The Rijksmuseum Bulletin, 2018
This article focuses on the ‘Merkelsche Tafelaufsatz’, a large centrepiece made by the
Nuremberg... more This article focuses on the ‘Merkelsche Tafelaufsatz’, a large centrepiece made by the
Nuremberg-based Wenzel Jamnitzer in 1549. The piece is known for its numerous life
casts of small creatures and flowers – real plants and animals placed in a mould with
material that was heated, causing the original to be calcined. The void thus created
was then filled with silver. Earlier research based on a contemporary French treatise
on the subject illustrates how these life casts, especially the animals, could have been
made. This article focuses on the casting of the flowers. An experiment recreating
the intricate aquilegia in the crowning piece shed light on the casting method the
goldsmith and his workshop used to achieve the delicate petals and fragile pistils and
stamens. The plants and animals on the centrepiece are identified, and other techniques
involved in creating the centrepiece as a whole, are described and examined. The cast
ornaments, the paint on some of the life casts and the reinforcement of the main
figure are discussed. The article concludes by demonstrating that the dedication
cartouche, always thought to have been left empty, must have borne an inscription
as some of the letters from it have been reconstructed with analytical techniques.
The Rijksmuseum Bulletin
The magnificent gilded silver ewer Adam van Vianen made in 1614 to commemorate his brother Paulus... more The magnificent gilded silver ewer Adam van Vianen made in 1614 to commemorate his brother Paulus van Vianen who had died the previous year in Prague, is the pinnacle of the kwabstijl, and of Dutch silversmithing in general. The execution of the raising and embossing is exceptional and had never seen before. Von Sandrart specifically stated in his book that Adam made the whole object out of one piece of silver. It is quite possible that Adam van Vianen applied himself to a quest that many sculptors undertook in the Renaissance: making an object under the most challenging circumstances in their area of expertise. A ewer traditionally consists of a body, foot, handle and a lid with a hinge, which are soldered or screwed together. Adam van Vianen, however, integrated all these separate parts into one dynamic, swirling form, and the absence of clearly separated parts seems to confirm that the ewer is made out of a single piece. To determine once and for all whether the ewer is made out ...
The so-called 'Merkelsche Tafelaufsatz', a centrepiece made by the Nuremberg goldsmith Wenzel Jam... more The so-called 'Merkelsche Tafelaufsatz', a centrepiece made by the Nuremberg goldsmith Wenzel Jamnitzer in 1549, is one of the most famous masterpieces in goldsmithing from the sixteenth century. For the opening of the new Rijksmuseum, the centrepiece needed conservation treatment, which provided the opportunity for an in-depth examination. One of the most interesting findings concerned the so far undiscovered remnants of a largely removed etched text on the silver plaque fixed to the bottom of the piece. The traces of the text, which must derive from the time Jamnitzer made the centrepiece, were non-destructively analysed with the AGLAE mapping system at the Musée du Louvre, and some letters could be discriminated. These results shed new light on the history of the piece and a possible special occasion for which this object may have been made.
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Papers by Joosje Van Bennekom
of the living tradition of metal casting established over a thousand years ago in
the region of Tamil Nadu. Purchased in 1935 from a Parisian dealer, it is one of the
highlights of the collection belonging to the Royal Asian Art Society in the Netherlands, which is exhibited at the Rijksmuseum. The interdisciplinary study presented
here links an art historical investigation of ancient texts and scholarly literature with
scientific analysis in an attempt to refine the art historical context and at the same
time flesh out what is known about the fabrication and provenance of the Nataraja
in the Rijksmuseum. The Nataraja was cast by the lost-wax method; x-ray images
confirm that the Shiva is solid-cast together with the halo. X-ray fluorescence
reveals an alloy consistent with other Chola-period bronzes but not necessarily a
pañcaloha alloy (five metals), which seems to be a modern tradition; the front hands
were apparently cast on separately as a repair, probably during casting or not long
after. Further evidence gathered from the sculpture and its soil encrustations (icp-ms
lead and neodymium isotope ratios, sem-edx and xrd) is briefly presented, and
supports earlier assumptions about the Nataraja. It appears to date from the twelfth
century and was under worship for a relatively short time before it was buried at
an unknown location in India. The presence of Indian earth and corrosion products
typical of burial imply that it did not re-enter a temple context for worship and
was not subject to major restoration before entering the art market in the early
twentieth century
Nuremberg-based Wenzel Jamnitzer in 1549. The piece is known for its numerous life
casts of small creatures and flowers – real plants and animals placed in a mould with
material that was heated, causing the original to be calcined. The void thus created
was then filled with silver. Earlier research based on a contemporary French treatise
on the subject illustrates how these life casts, especially the animals, could have been
made. This article focuses on the casting of the flowers. An experiment recreating
the intricate aquilegia in the crowning piece shed light on the casting method the
goldsmith and his workshop used to achieve the delicate petals and fragile pistils and
stamens. The plants and animals on the centrepiece are identified, and other techniques
involved in creating the centrepiece as a whole, are described and examined. The cast
ornaments, the paint on some of the life casts and the reinforcement of the main
figure are discussed. The article concludes by demonstrating that the dedication
cartouche, always thought to have been left empty, must have borne an inscription
as some of the letters from it have been reconstructed with analytical techniques.
of the living tradition of metal casting established over a thousand years ago in
the region of Tamil Nadu. Purchased in 1935 from a Parisian dealer, it is one of the
highlights of the collection belonging to the Royal Asian Art Society in the Netherlands, which is exhibited at the Rijksmuseum. The interdisciplinary study presented
here links an art historical investigation of ancient texts and scholarly literature with
scientific analysis in an attempt to refine the art historical context and at the same
time flesh out what is known about the fabrication and provenance of the Nataraja
in the Rijksmuseum. The Nataraja was cast by the lost-wax method; x-ray images
confirm that the Shiva is solid-cast together with the halo. X-ray fluorescence
reveals an alloy consistent with other Chola-period bronzes but not necessarily a
pañcaloha alloy (five metals), which seems to be a modern tradition; the front hands
were apparently cast on separately as a repair, probably during casting or not long
after. Further evidence gathered from the sculpture and its soil encrustations (icp-ms
lead and neodymium isotope ratios, sem-edx and xrd) is briefly presented, and
supports earlier assumptions about the Nataraja. It appears to date from the twelfth
century and was under worship for a relatively short time before it was buried at
an unknown location in India. The presence of Indian earth and corrosion products
typical of burial imply that it did not re-enter a temple context for worship and
was not subject to major restoration before entering the art market in the early
twentieth century
Nuremberg-based Wenzel Jamnitzer in 1549. The piece is known for its numerous life
casts of small creatures and flowers – real plants and animals placed in a mould with
material that was heated, causing the original to be calcined. The void thus created
was then filled with silver. Earlier research based on a contemporary French treatise
on the subject illustrates how these life casts, especially the animals, could have been
made. This article focuses on the casting of the flowers. An experiment recreating
the intricate aquilegia in the crowning piece shed light on the casting method the
goldsmith and his workshop used to achieve the delicate petals and fragile pistils and
stamens. The plants and animals on the centrepiece are identified, and other techniques
involved in creating the centrepiece as a whole, are described and examined. The cast
ornaments, the paint on some of the life casts and the reinforcement of the main
figure are discussed. The article concludes by demonstrating that the dedication
cartouche, always thought to have been left empty, must have borne an inscription
as some of the letters from it have been reconstructed with analytical techniques.