Papers by Miriam Truffa Giachet
HAL (Le Centre pour la Communication Scientifique Directe), Jan 21, 2021
PLOS ONE, 2020
The presence of glass beads in West African archaeological sites provides important evidence of l... more The presence of glass beads in West African archaeological sites provides important evidence of long-distance trade between this part of the continent and the rest of the world. Until recently, most of these items came from historical Sub-Saharan urban centers, well known for their role in the medieval trans-Saharan trade. We present here the chemical analysis by Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) of 16 glass beads found in three rural sites excavated during the past decade: the funerary site of Dourou-Boro and settlement sites of Sadia, in central Mali, as well as the settlement site of Djoutoubaya, in eastern Senegal, in contexts dated between the 7th-9thand the 11th-13thcenturies CE. Results show that the raw materials used to manufacture the majority of the glass most probably originated in Egypt, the Levantine coast and the Middle East. One bead is of uncertain provenance and shows similarities with glass found in the Iberian Peninsula and i...
Journal of Archaeological Science: Reports, 2019
The so-called Phoenician or Punic eye beads are a well-known type of glass artefacts circulating ... more The so-called Phoenician or Punic eye beads are a well-known type of glass artefacts circulating all over the Mediterranean Basin and Europe for most of the 1st millennium BCE. Glass beads were mostly produced in secondary workshops from imported raw glass or recycled artefacts but the specific sites of manufacture remain difficult to locate. Nevertheless, numerous chemical studies of glass from the area of interest proved that natronbased soda-lime-silica glass was the most widespread from 10th-9th century BCE to 8th-9th century CE. A glass eye bead typologically consistent with the Phoenician ones was unearthed during the archaeological excavation of the Nin-Bèrè 3 settlement site in Mali in a context dating between the 7th and the 5th centuries cal BCE. The chemical analysis by means of Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) has been carried out in order to confirm the characteristic composition of Mediterranean Iron Age glass. Results show the bead to be soda-lime silica glass fluxed with mineral soda, and coloured and opacified with cobalt, copper, and antimony. The minor and trace elements are also consistent with said composition. This exceptional find this far south expands greatly the area of distribution of these artefacts and it suggests a very early indirect contact between sub-Saharan Africa and the Mediterranean Basin. At the current state of research, this is the most ancient glass bead found south of the Sahara desert.
Polymer Degradation and Stability, 2014
Polymer Degradation and Stability, 2014
Heritage, 2024
Lacquered brass objects are widely present in scientific and technical heritage collections. Loca... more Lacquered brass objects are widely present in scientific and technical heritage collections. Localized atmospheric corrosion occurs on the metal when the coating fails to play its protective role. Although lacquered brass objects are not necessarily endangered by this phenomenon, the presence of dark, unpleasant corrosion spots alters the surface appearance, affecting the readability of the objects. Conservators are therefore frequently asked to clean these surfaces. We hereby present the results of a study conducted in the framework of the CleanLaB (Cleaning of Lacquered Brass) project at the Haute Ecole Arc of Neuchâtel for the cleaning of lacquered brass. This work investigates the effects of several gelled cleaning systems applied on artificially aged, lacquered brass samples to remove the corrosion products without affecting the integrity of the coating. The performance of complexing agents commonly used in conservation was compared on lacquered brass mock-ups coated with shellac resin by means of multiple non-invasive characterization and imaging techniques. The tests included conventional complexing agents like sodium citrate and disodium ethylenediaminetetraacetic acid, as well as a bio-originated system based on deferoxamine, a microbial metal chelator investigated as a green alternative in cleaning formulations.
Les perles en verres sont des artefacts tres repandus sur les sites archeologiques ouest-africain... more Les perles en verres sont des artefacts tres repandus sur les sites archeologiques ouest-africains et leur etude est fondamentale pour la reconstitution des dynamiques d’echange entre l’Afrique subsaharienne et le reste du monde a differentes epoques. Cette these concerne l’etude archeometrique systematique de 954 perles en verre decouvertes lors des fouilles archeologiques de 10 sites au Mali, au Senegal et au Ghana, dans des contextes dates entre le 7eme-5eme siecle BC et le 18eme-20eme siecle AD. Toutes les perles ont ete analysees visuellement afin d’en obtenir une classification techno-stylistique et la plupart de l’assemblage a ete analyse chimiquement par LA-ICP-MS afin d’en creer une classification chimique. La comparaison des compositions avec les donnees de la litterature a permis, enfin, de retracer l’origine probable des verres, notamment le bassin mediterraneen et l’Asie, a travers les echanges transsahariennes, dans un premier temps et l’Europe, par le commerce atlanti...
An analytical survey was conducted of animation cels in the Walt Disney Animation Research Librar... more An analytical survey was conducted of animation cels in the Walt Disney Animation Research Library (ARL) collection, made for animated films from 1929 to 2003, that addressed three main topics: (1) characterization of cel polymers and plasticizers; (2) assessment of cel degradation in storage; and (3) assessment of cel degradation and microenvironments in passe-partout mounts. FTIR was helpful in differentiating the main polymer types: cellulose nitrate, cellulose diacetate, cellulose triacetate, and polyester. The majority of the cels were made from cellulose diacetate before 1981, and cellulose triacetate thereafter. Pyrolysisgas chromatography/mass spectrometry (Py-GC/MS) identified a number of distinct plasticizer mixtures–primarily triphenyl phosphate mixed with phthalates–in the diacetate and triacetate cels. Estimates of the acetyl content by gas chromatography/mass spectrometry, which assessed the degree of substitution in the cellulose acetate cels, revealed that few cels s...
Avec la collaboration de: Luis Giraldes 1 et David Glauser 1 , techniciens nous ayant appuyé dans... more Avec la collaboration de: Luis Giraldes 1 et David Glauser 1 , techniciens nous ayant appuyé dans notre travail, tant au Sénégal qu'en Suisse, et les étudiants européens et africains
Cet article presente les resultats de la campagne de terrain menee au Senegal oriental en 2017 da... more Cet article presente les resultats de la campagne de terrain menee au Senegal oriental en 2017 dans le cadre du programme international « Peuplement humain et paleoenvironnement en Afrique ». Il integre les resultats de deux projets complementaires : le projet ANR-FNS CheRCHA, ainsi que le projet FNS Faleme. Le premier vise a reconstituer le cadre chronostratigraphique et les evolutions culturelles au Pleistocene et a l’Holocene ancien et moyen dans la vallee de la Faleme, tandis que le second est cible sur les dynamiques techniques des deux derniers millenaires au Senegal oriental.
This paper focuses on the chemical and physical characterization of cellulose acetate animation c... more This paper focuses on the chemical and physical characterization of cellulose acetate animation cels from the Walt Disney Animation Research Library dating from 1931 to 2003. The aim of this study is to compare the composition and date of the cels to their degree of deterioration relative to the storage conditions. The chemical composition was investigated by Fourier-transform infrared spectrometry (FTIR) to identify the polymer base material, and by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) to characterize the plasticizer composition. Thermomechanical analysis (TMA) was used to investigate the mechanical behavior of the cels.
Coatings
The application of varnishes on the surface of metal objects has been a very common practice sinc... more The application of varnishes on the surface of metal objects has been a very common practice since antiquity, both for protective and aesthetic purposes. One specific case concerns the use of tinted varnishes on copper alloys in order to mimic gilding. This practice, especially flourishing in the 19th century for scientific instruments, decorative objects, and liturgical items, results in large museum collections of varnished copper alloys that need to be preserved. One of the main challenges for conservators and restorers deals with the identification of the varnishes through non-invasive and affordable analytical techniques. We hereby present the experimental methodology developed in the framework of the LacCA and VERILOR projects at the Haute École ARC of Neuchâtel for the identification of gold varnishes on brass. After extensive documentary research and analytical campaigns on varnished museum objects, various historic shellac-based varnishes were created and applied by differe...
Coatings, 2021
The application of varnishes on the surface of metal objects has been a very common practice sinc... more The application of varnishes on the surface of metal objects has been a very common practice since antiquity, both for protective and aesthetic purposes. One specific case concerns the use of tinted varnishes on copper alloys in order to mimic gilding. This practice, especially flourishing in the 19th century for scientific instruments, decorative objects, and liturgical items, results in large museum collections of varnished copper alloys that need to be preserved. One of the main challenges for conservators and restorers deals with the identification of the varnishes through non-invasive and affordable analytical techniques. We hereby present the experimental methodology developed in the framework of the LacCA and VERILOR projects at the Haute École ARC of Neuchâtel for the identification of gold varnishes on brass. After extensive documentary research and analytical campaigns on varnished museum objects, various historic shellac-based varnishes were created and applied by differe...
Coatings, 2021
The application of varnishes on the surface of metal objects has been a very common practice sinc... more The application of varnishes on the surface of metal objects has been a very common practice since antiquity, both for protective and aesthetic purposes. One specific case concerns the use of tinted varnishes on copper alloys in order to mimic gilding. This practice, especially flourishing in the 19th century for scientific instruments, decorative objects, and liturgical items, results in large museum collections of varnished copper alloys that need to be preserved. One of the main challenges for conservators and restorers deals with the identification of the varnishes through non-invasive and affordable analytical techniques. We hereby present the experimental methodology developed in the framework of the LacCA and VERILOR projects at the Haute École ARC of Neuchâtel for the identification of gold varnishes on brass. After extensive documentary research and analytical campaigns on varnished museum objects, various historic shellac-based varnishes were created and applied by differe...
Coatings, 2021
The application of varnishes on the surface of metal objects has been a very common practice sinc... more The application of varnishes on the surface of metal objects has been a very common practice since antiquity, both for protective and aesthetic purposes. One specific case concerns the use of tinted varnishes on copper alloys in order to mimic gilding. This practice, especially flourishing in the 19th century for scientific instruments, decorative objects, and liturgical items, results in large museum collections of varnished copper alloys that need to be preserved. One of the main challenges for conservators and restorers deals with the identification of the varnishes through non-invasive and affordable analytical techniques. We hereby present the experimental methodology developed in the framework of the LacCA and VERILOR projects at the Haute École ARC of Neuchâtel for the identification of gold varnishes on brass. After extensive documentary research and analytical campaigns on varnished museum objects, various historic shellac-based varnishes were created and applied by different methods on a range of brass substrates with different finishes. The samples were then characterized by UV imaging and infrared spectroscopy before and after artificial ageing. The comparative study of these two techniques was performed for different thicknesses of the same varnish and for different shellac grades in order to implement an identification methodology based on simple non-invasive examination and analytical tools, which are accessible to conservators.
PLoS ONE, 2020
The presence of glass beads in West African archaeological sites provides important evidence of l... more The presence of glass beads in West African archaeological sites provides important evidence of long-distance trade between this part of the continent and the rest of the world. Until recently, most of these items came from historical Sub-Saharan urban centers, well known for their role in the medieval trans-Saharan trade. We present here the chemical analysis by Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) of 16 glass beads found in three rural sites excavated during the past decade: the funerary site of Dourou-Boro and settlement sites of Sadia, in central Mali, as well as the settlement site of Djoutoubaya, in eastern Senegal, in contexts dated between the 7 th-9 th and the 11 th-13 th centuries CE. Results show that the raw materials used to manufacture the majority of the glass most probably originated in Egypt, the Levantine coast and the Middle East. One bead is of uncertain provenance and shows similarities with glass found in the Iberian Peninsula and in South Africa. One bead fragment found inside a tomb is a modern production, probably linked to recent plundering. All of these ancient beads were exchanged along the trans-Saharan trade routes active during the rise of the first Sahelian states, such as the Ghana and the Gao kingdoms, and show strong similarities with the other West African bead assemblages that have been analysed. Despite the remoteness of their location in the Dogon Country and in the Falé mé River valley, the beads studied were therefore included in the long-distance trade network, via contacts with the urban commercial centers located at the edge of the Sahara along the Niger River and in current southern Mauretania. These results bring a new light on the relationships between international and regional trade in Africa and highlight the complementarity between centres of political and economic power and their peripheries, important because of resources like gold for eastern Senegal.
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Papers by Miriam Truffa Giachet