An interdisciplinary approach to the study of colour in portuguese manuscript illuminations

Dissertação apresentada para obtenção do Grau de Doutor em Conservação e Restauro, especialidade Teoria, História e Técnicas, pela Universidade Nova de Lisboa, Faculdade de Ciências e TecnologiaThis dissertation explores the materials used and practice undertaken by medievalist illuminators to produce some remarkable Portuguese illuminations from the 12th and 13th centuries. New techniques and applications were also explored to better characterize the paints’ composition. In the first part of this dissertation a methodology to study the illuminations of nine Lorvão scriptorium manuscripts, selected as representative and for being suitable for an analytical study, was developed and used to characterize the Lorvão’s scriptorium medieval palette. Further studies were performed in two very important dated manuscripts: Apocalypse and Book of Birds. Comparing them with other Portuguese or European copies it was concluded that the Lorvão Apocalypse differs from other contemporaneous Beatus Commentaries, either on the uniqueness of the colours used –orange, red and yellow- or on iconographic choices; and the Book of Birds was found to have many similarities with the copy made on Santa Cruz monastery. Based on medieval written sources, a database of paint reconstructions was built and characterized by HPLC-DAD, UV-VIS, μ-FTIR, μ-EDXRF, μ-Raman and μ-spectrofluorimetry. It allowed an easier description of the manuscripts’ paints components by non-invasive techniques: binders, organic and inorganic pigments. The last ones were found singly applied or in a mixture of two or three pigments, such as the orange paint of the Apocalypse or the blue paint of the Book of Birds. When mixtures were found, EDXRF analysis was used to quantify the inorganic paint components. The red lead degradation product in most of orange paint applied on Lorvão Apocalypse’s folia was recognized as galena, using μ-Raman and XRD techniques. The second part of this dissertation outcomes from the study of red organic colorants that could be expected in medieval illumination manuscripts, based on madder, lac dye and cochineal. Their main chromophores: alizarin, purpurin, acid laccaic A and carminic acid, were photochemically and photophysically characterized. Photodegradation studies were performed in homogeneous (alizarin, purpurin and carminic acid) and heterogeneous media. Based on this study, the use of microspectrofluorimetry as a new technique to identify red colorants was applied on red lake paint reconstructions, on the Book of Birds, on millenary Andean textiles (a collaboration with Museum of Fine Arts, Boston) and applied on impressionists’ (Vincent van Gogh or Pissarro) paintings’ cross-sections (a collaboration with Red Lakes international project). It revealed that it is possible to characterize red lake pigments and paints based on alizarin, purpurin and eosin (weak, medium and strong emitters) and that can also be used as a semi-quantitative method for madder lake pigments, enabling the determination of purpurin lake ratio in a mixture of purpurin and alizarin.FCT and Feder for funding this work through the projects POCTI/EAT/33782/2000, POCI/QUI/55672/2004 and PTDC/EAT/65445/2006, and also the PhD grant SFRH/BD/36130/200