Luiz Antônio Cruz Souza

Análise de pinturas rupestres do Abrigo do Janelão (Minas Gerais) por microscopia raman

Rock art paintings from Abrigo do Janelao (Minas Gerais, Brazil) were non-destructively investigated by Raman Microscopy, aiming at the identification of materials used, their interaction and degradation. This technique is particularly tailored for heterogeneous samples and allows unequivocal identification of the substances present in the investigated sample. Pigments, were identified together with products of microbiological degradation; no binders were detected. White pigment was identified as calcite (CaCO3), whereas charcoal was used as black, goethite (α-FeOOH) as yellow and hematite (α-Fe2O3) as red. Whewellite (CaC2O4.H2O) and weddelite (CaC2O4.2H2O) were detected and their origin was assigned to degradation products from microbiological activity.

Metal corrosion in polychrome baroque lead sculptures: a case study

Esculturas policromadas de Pb do Museu do Oratorio em Ouro Preto (Minas Gerais, Brasil), expostas em um mostruario de vidro foram severamente degradadas. Os produtos de corrosao foram analisados por difratometria de raios X (XRD), espectroscopia no infravermelho com transformada de Fourier (FTIR), microscopia eletronica de varredura (SEM), fluorescencia de raios X por dispersao de energia (EDX) e microscopia Raman, e constatou-se a formacao majoritaria de carbonatos e formiatos de Pb. Embora carbonatos sejam comuns na corrosao atmosferica de Pb, formiatos podem ser formados tanto pela acao de acido formico quanto de formaldeido, sendo sua origem um ponto importante a ser investigado. Simulacoes ambientais com tiras de Pb expostas a possiveis fontes desses compostos orgânicos volateis possibilitaram concluir que o processo de degradacao foi causado principalmente pelo processo de cura da tinta utilizada na base do mostruario. Contudo, produtos de limpeza, que podem conter formaldeido como conservante, mostraram-se potencialmente capazes de causar danos a objetos de chumbo, acelerando sua corrosao. Polychrome lead sculptures from Oratory Museum in Ouro Preto (Minas Gerais, Brazil) kept inside a glass showcase were severely degraded. The formed corrosion products were analyzed by X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray fluorescence (EDX) and Raman microscopy and proved to be mostly Pb carbonates and formates. Although carbonate is a very common finding in Pb atmospheric corrosion, Pb formates can be formed by the action of formic acid or formaldehyde, being their origin a key point to be investigated. Environmental simulations with Pb coupons exposed to possible sources of these volatile organic compounds led to the conclusion that the degradation process was caused mainly by the curing process of the painted showcase baseplate. However, cleaning products, which can also contain formaldehyde as preservative, proved to be potentially harmful to Pb, accelerating its corrosion.

A Note on the Products of the Reaction of AMT with Bronze and with Three Corrosion Products of Bronze

Abstract The compound 5-amino-2-mercapto-1,3,4-thiadiazole (AMT) is utilized in the conservation of archaeological and artistic bronze artifacts, for their protection and for the removal of corrosion products. Many authors have discussed the utility and efficacy of this, but few have studied the products resulting from the reaction of AMT with bronze or with the corrosion products of bronze; this leaves the restorer with many doubts concerning the acceptability of this method. This paper discusses the study of products obtained from the reaction of AMT with synthesized corrosion products of bronze (malachite, paratacamite and brochantite) and with the commercial bronze alloy TM 23 (Cu 72%, Pb 15%, Zn 8% and Sn 5%). It was found that the film obtained from the direct reaction of AMT with the bronze alloy can be AMT itself, or the metallic complex Cu(C2H2N3S2)2·H2O if AMT is applied in a solution of an oxidizing acid. These results are expected to be of value to conservation scientists and restorers/ conservators concerned with the use of AMT for the conservation of bronze artifacts.

The use of industrial paint on wood by Lygia Clark

Contemporary art presents various challenges and questions for those responsible for its preservation. Faced with new variables including but not limited to the use of modern and diverse materials, complexity of construction, in addition to conceptual and intangible questions, the profession needs to re-examine conservation and restoration theories developed thus far. This communication presents an investigation (Giovani et al., 2015) into the paintings of the Brazilian artist Lygia Clark (born Belo Horizonte 1920, died Rio de Janeiro 1988) during the 1950s, with a focus on four works made from industrial paint on wood. They are: Superfície Modulada N° 12 (1956), Planos em Superfície Modulada N° 3 (1957), Espaço Modulado N° 4 (1958), and Ovo – Contra Relevo (1959). The paintings belong to the Sattamini collection,1 and are on loan to the Museum of Contemporary Art of Niterói, Rio de Janeiro, Brazil. These particular paintings gave the opportunity to carry out research into some highly significant works which also provide a snapshot of Clark’s career over a short period. The goals were to understand their production, the way the use of industrial materials was incorporated into the artist’s work, and the context in which these were used. Appropriate knowledge of these materials and techniques is essential for understanding the deterioration processes now apparent in the works, and how their materials can affect their appearance and the inherent concept of geometrical abstractionism explored by the artist, given that aesthetic enjoyment is a fundamental part of the artist’s intention and the viewer’s participation. By improving knowledge of her materials, conservators will gain insights that could help with the dating of the works. Additionally, the study will lead to improved knowledge of vulnerability, and the interaction of the construction materials with agents of deterioration. This will lead to the development of safer storage and conservation procedures based on the properties of her materials. This investigation aims to assist and contribute to the field of conservation science through imaging and documentation, documentary research, the creation of reconstructions and the use of physic-chemical analytical techniques. The research was developed in collaboration with LACICOR, the Conservation Science Laboratory of the Universidade Federal de Minas Gerais, Brazil, and had the support of an interdisciplinary team for interpretation and discussion of results. First, as much information as possible was collected from different sources including art historical studies and personal records, combined with investigation of the historical and social context of the period when these artworks were made, and a survey of the products available at the time. Valuable information was found in one of the artist’s expense notebooks, where materials were listed for her paintings. The artist listed two commercial paint brands used during her painting in the 1950s, WandaTM and PoliduraTM, and also noted the material used for priming the wooden support, and the characteristics of the finishing paints. It is known that these paints were made from nitrocellulose lacquers and alkyd paints, used for the painting of automotive vehicles.2 Another source of information vwas found in the newspaper Diário de Notícias, in which Clark declared during an interview (Diário de Notícias, 1957):

Scientific analysis and historical aspects as tools in the legal investigation of paintings: A case study in Brazil

The faker makes use of several strategies to give credibility to his work, as for example by copying artists style or by using artificial aging techniques. The characterization of artistic materials, such as pigments, binding media and supports through chemical and/or physico-chemical analysis, coupled with art historical information is essential to establish the non-authenticity of works of art. This paper presents a contribution in a legal case regarding paintings attributed to important Brazilian and European artists such as Candido Portinari, Juan Gris, Camille Pissarro, and Umberto Boccioni, among others. In the investigation, modern synthetic painting materials were identified in all the ground layers of the suspected paintings. The use of diverse instrumental analytical techniques such as Fourier transform infrared spectroscopy, polarized light microscopy and pyrolysis-gas chromatography/mass spectrometry enabled this characterization. The results demonstrated the presence of titanium dioxide, calcium carbonate and kaolin as inorganic components of the paints, and polyvinyl acetate copolymerized with vinyl versatates or diisobutylphtalate as binding media in the ground layers of the paintings. The results obtained, along with art historical information and art technological studies, were very important in the judicial process, due to the possibility to use titanium dioxide and polyvinyl acetate copolymerized with vinyl versatates as chronological markers.

A multimedia information system for administrative, scientific and intervention data in conservation-restoration of cultural movable properties

This paper describes the process of modelling and implementing a multimedia information system for CECOR-Center for Conservation and Restoration of Cultural Movable Properties. The new system includes a multimedia system which contains information about the restored objects, their materials and techniques, images generated by methods of diagnosis, results of scientific analysis, etc. The new system also includes administrative information about the contacts with the clients, payments and the current status of the object, regarding its restoration process.