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A Closer Look at Heritage Systems from Medieval Colors to Modern and Contemporary Artworks
Publication . Melo, Maria J.; Vieira, Márcia; Nabais, Paula; Neves, Artur; Pamplona, Marisa; Angelin, Eva Mariasole; LAQV@REQUIMTE; DCR - Departamento de Conservação e Restauro; Instituto de Estudos Medievais (IEM); Faculdade de Ciências e Tecnologia (FCT); MDPI - Multidisciplinary Digital Publishing Institute
This microreview, conducted by interdisciplinary teams, examines complex heritage material systems, such as medieval colors and modern and contemporary artworks. Our multi-analytical approach, a significant aspect of our research, is a means to this end. The conservation of works of art is our shared goal, as it ensures their accessibility and the transfer of cultural heritage to future generations. We seek to interpret the damage, usefulness, and innovation of the experimental design in this context. As Jan Wouters rightly points out, “The terminology used nowadays to describe the potential damage to objects caused by analysis should be refined beyond the destructiveness/non-invasiveness polarization. A terminology should include at least degree level intervention (low, medium, high), usefulness, and innovation”. Complementing micro- or sub-micro-sampling with the appropriate analytical methods is crucial, as exemplified in medieval, modern, and contemporary collections studies. Finally, a novel perspective for exploring the information contained in the multiscale heterogeneity of organic historical materials is envisaged, and it includes UV/Visible photoluminescence spectral imaging using a low-intensity ultraviolet synchrotron beam.
Best billiard ball in the 19th century
Publication . Neves, Artur; Friedel, Robert; Melo, Maria J.; Callapez, Maria Elvira; Vicenzi, Edward P.; Lam, Thomas; LAQV@REQUIMTE; DCR - Departamento de Conservação e Restauro; National Academy of Sciences
The demystification of how 19th-century novelly designed materials became significant elements of modern technological, economic, and cultural life requires a complete understanding of the material dimensions of historical artifacts. The objects frequently described as the earliest manufactured plastic products—the billiard balls made by John Wesley Hyatt and his associates from the late 1860s—are examined closely for the first time and are found to be more complex and functionally more successful than has been described. Modern analytical techniques such as optical microscopy, scanning electron microscope—energy dispersive X-ray spectroscopy, X-ray fluorescence, micro-Fourier transformed infrared, and handheld/micro-Raman spectroscopies were used to reveal the complex composition of the Smithsonian Institution’s “original” 1868 celluloid billiard ball. Comparisons with billiard and pool balls commercialized from the 1880s to the 1960s showed an unexpected consistency in material formulations. All specimens were made of an unprecedented composite material prepared with a mixture of cellulose nitrate, camphor, and ground bone; the source of the bone was identified as cattle by peptide mass fingerprint (ZooMS). Patent specifications and contemporary journal descriptions explained how and when these formulations emerged. Combining the technical analyses of compositions with a careful reading of the historical record and contemporary descriptions reveals the key elements of the first successful efforts to substitute materials to assist the survival of endangered animals.
Safeguarding our dentistry heritage
Publication . Neves, Artur; Friedel, Robert; Callapez, Maria Elvira; Swank, Scott D.; LAQV@REQUIMTE; DCR - Departamento de Conservação e Restauro; SpringerOpen
In the 1870s, dentures were one of the first products made with celluloid, the first semi-synthetic plastic. Despite the significance of denture development in the history of celluloid and plastics, the chemical characterization of dentures in museum collections has never been attempted. It is urgent to assess the extent of celluloid heritage in denture collections due to the high degradation risk that this material imposes. In this work, 21 dentures from the National Museum of American History and from the Dr. Samuel D. Harris National Museum of Dentistry were characterized using a multi-analytical methodology using handheld Raman, X-Ray fluorescence, and micro-Fourier transformed infrared spectroscopies. All dentures were successfully characterized: 12 are made of celluloid, 4 of vulcanized rubber, 2 of phenol–formaldehyde, 2 of polyvinyl chloride—polyvinyl acetate copolymer (PVC-PVAc) and 1 of polymethyl methacrylate (PMMA). The identification of the dentures’ base materials allowed a better understanding of their history and posed new questions about their conservation. Handheld Raman was demonstrated as an excellent in-situ tool for the study of polymeric materials.
The challenge of cellulose nitrate-coated fabrics
Publication . Neves, Artur; Ferreira, Joana Tomás; Friedel, Robert; Callapez, Maria Elvira; DCR - Departamento de Conservação e Restauro; LAQV@REQUIMTE; Associação Profissional de Conservadores-Restauradores de Portugal (ARP)
In the 19th century, significant linen and leather imitation products were invented using cellulose nitrate-coated fabrics, including celluloid detachable collars and Fabrikoid artificial leather, now preserved in the Hagley Museum and Library, USA. Using optical microscopy, µRaman, and µFourier Transformed Infrared spectroscopies, this study highlights the need for characterizing the heterogeneity of these materials at the microscale. While the detachable collars have well-preserved fabric coatings composed of cellulose nitrate, camphor, anatase (TiO2), and carbon-based particles, Fabrikoid’s pigmented cellulose nitrate-castor oil systems show problems. Our molecular data align with a 1922 report on Fabrikoid degradation, revealing free fatty acids and carboxylates formed due to oil oxidation. This is concerning as these materials were used until the 1960s, demonstrated by the analysis of objects from the National Museum of Costumes in Portugal. Future studies should address the compatibility of cellulose nitrate with fatty acids and the reactivity of additives in these systems.
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Fundação para a Ciência e a Tecnologia
Programa de financiamento
3599-PPCDT
Número da atribuição
2022.05086.PTDC