A carregar...
Projeto de investigação
Sem título
Financiador
Autores
Publicações
A Study on the Degradation of Iron Gall Inks and to Preserve Them Using Green Approaches
Publication . Teixeira, Natércia; Nabais, Paula; Otero, Vanessa; Díaz Hidalgo, Rafael Javier; Ferretti, Matteo; Licchelli, Maurizio; Melo, Maria J.; LAQV@REQUIMTE; Faculdade de Ciências e Tecnologia (FCT); VICARTE - Vidro e Cerâmica para as Artes; DCR - Departamento de Conservação e Restauro; MDPI - Multidisciplinary Digital Publishing Institute
Inks from the 12th to the 17th century were aged, and a multi-analytical approach was used for their identification based on HPLC–DAD–MS, microFTIR, and microRaman. Colorimetry analysis was also performed. After 6 years of application on filter paper, three inks were selected to be cleaned using a novel green approach based on a chemically crosslinked gel to remove unwanted materials from the ink surface. A Braga ink produced in 2018 was also tested. Two degradation products were identified; iron sulfate was the main degradation product in the Braga ink. For Montpellier, Guadalupe, and QI.8 inks, the main degradation product was a complex of iron with ellagic acid. These compounds were accurately confirmed using microFTIR. Several tests were performed to clean these degradation products with the gels. The Braga ink was cleaned with 10% ethanol in water, which was included in the gel, and the iron sulfate was removed within 15 s of application. On the other hand, the complex of iron with ellagic acid demanded longer application times; we used 2 min and repeated the application until the compound was removed. The novelty of this research has practical implications for the conservation of historical documents and artworks.
Between past and future
Publication . Melo, Maria João; Nabais, Paula; Vieira, Márcia; Araújo, Rita; Otero, Vanessa; Lopes, João; Martín, Lourdes; LAQV@REQUIMTE; DCR - Departamento de Conservação e Restauro; Instituto de Estudos Medievais (IEM); VICARTE - Vidro e Cerâmica para as Artes; Elsevier
Heritage materials are highly complex systems of unknown and intrinsically heterogeneous compositions and unmonitored long-term modifications. In this microreview, we describe our interdisciplinary approach, its importance to new treatments tailored to prevent changes to historical colours, and innovative strategies for their identification in artworks. We illustrate our methodology through the study of medieval Islamic manuscripts from the Fondo Ka'ti. These advanced studies have shown the remarkable properties of ancient dyes, their resilience and durability, properties designed by our ancestors through sustainable materials processing. This lost knowledge can be shared with the community empowering them to create new sustainable applications, from unique art pieces to regional value-added products.
Iron-gall inks
Publication . Melo, Maria Joao; Otero, Vanessa; Nabais, Paula; Teixeira, Natercia; Pina, Fernando; Casanova, Conceicao; Fragoso, Sara; Sequeira, Silvia O.; DCR - Departamento de Conservação e Restauro; LAQV@REQUIMTE; Instituto de Estudos Medievais (IEM); VICARTE - Vidro e Cerâmica para as Artes; DQ - Departamento de Química; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); SpringerOpen
Iron-gall inks are an essential element of our written cultural heritage that is at risk of a total loss due to degradation. This degradation leads to the loss of the support, particularly the cellulose-based support. Intending to stabilize it, we have come a long way from the nineteenth-century cellulose nitrate laminations to the relatively recent phytate treatments; nevertheless, less invasive treatments are needed. To pave the way for developing safer and more sustainable treatments, tailored as much as possible to the object, this paper reviews the conservation treatments and the advances that have taken place over the last decade in our understanding of the degradation mechanisms of iron-gall inks, based on a careful selection of references to support a concise microreview. This discussion is based on the currently accepted models based on the Fe3+-gallate and the identification of degradation products for iron-gall inks observed in heritage objects, including manuscripts dating from the fourteenth to seventeenth centuries and drawings from the fifteenth to nineteenth centuries. The degradation promoted by iron-gall inks induces scission of cellulose through acid catalysis and/or redox reactions. The causes of these acid-base and redox reactions are also assessed. Finally, we detail the state-of-the-art conservation treatments used to mitigate iron gall ink deterioration, covering treatments from the late nineteenth century to the beginning of the twentieth century, followed by the presentation of current phytate treatments and new postphytate treatments.
The making of black inks in an Arabic treatise by al-Qalalūsī dated from the 13th c.
Publication . Díaz Hidalgo, Rafael Javier; Córdoba, Ricardo; Grigoryan, Hermine; Vieira, Márcia; Melo, Maria J.; Nabais, Paula; Otero, Vanessa; Teixeira, Natércia; Fani, Sara; Al-Abbady, Hossam; DCR - Departamento de Conservação e Restauro; LAQV@REQUIMTE; VICARTE - Vidro e Cerâmica para as Artes; SpringerOpen
For the first time, this paper systematises the medieval preparation of black writing inks found in the important thirteenth century Andalusian technical treatise written by Muhammad ibn Idrīs ibn al-Qalalūsī (1210–1308). We present the Arabic version of this extraordinary text (‘The gifts of the wise men on the curiosities of the substances’), and its first English translation, as well as discuss key aspects of the processes that remain missing or are unclear indications. In this work, we studied the iron gall inks based on galls, where no other phenolic source is present. In this pedagogical treatise, the recipes for these black iron-gall inks are organised and classified by the gallnuts extraction method used: boiling (decoction), squeezing and infusion, with water being the only solvent used. The inks selected were reproduced and characterised through a multi-analytical approach. Quantification was performed by HPLC–DAD (high performance liquid chromatography with diode array detectors in the UV–VIS), showing that gallic acid is a minor compound in the gall extracts prepared following al-Qalalūsī instructions. In all the recipes, the higher concentration compounds in the gall extracts are the gallotannins pentagalloylglucose and hexagalloylglucose, ranging from 79 to 50% of the phenolic compounds. This supports the results of Raman and infrared spectroscopies. A comparison with medieval Iberian recipes was also done, which served to reinforce our previous results that show water as the sole solvent extracts with much lower yields than mixed solvents (water plus white wine or vinegar).
Unidades organizacionais
Descrição
Palavras-chave
Contribuidores
Financiadores
Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
3599-PPCDT
Número da atribuição
PTDC/QUI-OUT/29925/2017