Characterization of historically relevant materials in the context of art & conservation studies

Team: João Lopes, Jorge Sarraguça



Portuguese medieval manuscripts

Medieval illuminated manuscripts range among the most valuable objects of our European cultural heritage. Portuguese codices date from the foundation of Portugal as a kingdom and are testimonies of medieval ideas, religion and policy. St. Cruz, St. Mamede of Lorvão and Alcobaça are important in the context of political strategy of the Reconquest, which experienced their creation of monasteries for the maintenance, under the Christian domination, of recently conquered territories to Muslims, assuming the function of maintaining the peace and the articulation of the social order. This research line proposes to explore the issues related with the symbolic and social meaning of colour in medieval Portuguese illuminations, produced during the twelfth and first quarter of the thirteen centuries in the Alcobaça, Lorvão and St Cruz monasteries. Colour use and production in Portuguese medieval illuminations was a consequence of the technology available as well as of cultural and artistic options; by defining the specificities of its use and production we will contribute to fingerprint the influences of the three different cultures that coexisted in Portugal at that time, Arab, Jewish and Christian.

(collaboration with the Department of Conservation and Restauration of the New University of Lisbon)


cochinealsCochineal species

Identification of American cochineal species (Dactylopius genus) can provide important information for the study of historical works of art, entomology, cosmetics, pharmaceuticals and foods. Validated species of Dactylopius, including the domesticated cochineal D.coccus, were analysed by high-performance liquid chromatography with diode array detector (HPLC-DAD) and submitted to multivariate data analysis, in order to discriminate the species and hence construct a reference library for a wide range of applications. Principal components analysis (PCA) and partial least squares discriminant analysis (PLSDA) models successfully provided accurate species classifications. This library can be applied to the identification of historical insect specimens of unidentified species, mostly dating from the 19th century. With this approach it was possible to identify anomalies in how insects were labelled historically, as several of them were revealed not to be cochineal. This approach has shown that HPLC-DAD, in combination with suitable chemometric methods, is a powerful approach for discriminating related cochineal species.

[collaboration with the Department of Conservation and Restauration of the New University of Lisbon]


  • Ana Serrano, Micaela Sousa, Jessica Hallett, Monique S. J. Simmonds, Mark Nesbitt, and João A. Lopes* (2013) Identification of Dactylopius cochineal species with high-performance liquid chromatography and multivariate data analysis, Analyst, 2013, 138 (20), 6081 – 6090 [doi: 10.1039/C3AN00052D]
  • Miguel CP, Lopes JA*, Clarke M, Melo MJ (2012) Combining infrared spectroscopy with chemometric analysis for the characterization of proteinaceous binders in medieval paints, Chemom. Intell. Lab. Syst., 119, 32-38
  • Ana Serrano, Micaela M. Sousa*, Jessica Hallett, João A. Lopes, Conceição Oliveira (2011) A New Methodology for the Analysis of Natural Red Dyes (Cochineal) in Textiles of Historical Importance using High Performance Liquid Chromatography with Diode Array Detector and Multivariate Data Analysis, Anal. Bioanal. Chem., 401, 735-743
  • Sousa MM, Melo MJ*, Parola AJ, Melo JSS , Catarino F, Pina F, Cook F, Simmonds MSJ, Lopes JA (2008) Flavylium chromophores as species markers for Dragon’s blood resins from Dracaena and Daemonorops trees, J. Chrom. A, 1209, 153-161
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