A Spectroscopic Study of Brazilwood Paints in Medieval Books of Hours Maria Joa ˜ o Melo, a,b, * Vanessa Otero, a,b Tatiana Vitorino, a,b Rita Arau ´ jo, a,b Va ˆ nia S.F. Muralha, a,c Ana Lemos, d Marcello Picollo e a Faculdade de Cie ˆncias e Tecnologia, Universidade Nova de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal b Departamento de Conservac ¸a ˜o e Restauro, and REQUIMTE-CQFB, Universidade do Porto, R.D. Manuel II, Apartado 55142, 4051- 401 Porto, Portugal c Research Unit VICARTE: Vidro e Cera ˆ mica para as Artes, Faculdade de Cie ˆncias e Tecnologia, Universidade Nova de Lisboa, Monte da Caparica, Portugal d Instituto de Estudos Medievais, Faculdade de Cie ˆ ncias Sociais e Humanas, Universidade Nova de Lisboa, Avenida de Berna 26-C, 1069-061 Lisboa, Portugal e Nello Carrara Institute of Applied Physics of the National Research Council (IFAC-CNR), Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy In this work, microspectrofluorimetry was for the first time applied to the identification of the red organic lakes that are characteristic of the lavish illuminations found in 15 th century books of hours. Microspectrofluorimetry identified those red paints, ranging from opaque pink to dark red glazes, as brazilwood lakes. An unequivocal characterization was achieved by comparison with reference paints produced following recipes from the medieval treatise The Book on How to Make Colours, and was further confirmed by fiber optic reflectance spectroscopy (FORS). For these treasured cultural objects, microspectrofluorimetry and FORS proved to be the only techniques that could identify, in situ or in microsamples, the chromophore responsible for the pinkish hues: a brazilein-Al 3þ complex. Additionally, a multi-analytical approach provided a full characterization of the color paints, including pigments, additives, and binders. Microspectroscopic techniques, based on infrared and X-ray radiation, enabled us to disclose the full palette of these medieval manuscripts, including the elusive greens, for which, besides malachite, basic copper sulfates were found; Raman microscopy suggested a mixture of brochantite and langite. Infrared analysis proved invaluable for a full characterization of the additives that were applied as fillers or whites (chalk, gypsum, and white lead) as well as the proteinaceous and polysaccharide binders that were found pure or in mixture. Index Headings: Microspectrofluorimetry; Fiber optic reflectance spectroscopy: FORS; l-Fourier transform infrared spectroscopy: l- FT-IR; Raman microscopy: l-Raman; Brazilwood; Books of hours; Medieval pigments. INTRODUCTION The study of the molecular palette used to produce three books of hours from Pala´cio Nacional de Mafra (PNM) collection, dated from the 15 th century, was carried out, with particular emphasis on the study of the organic reds responsible for carmine and pink tones. These illuminated manuscripts are not just vehicles for the transmission of texts and images; they also include some of the masterpieces of medieval art. 1–3 Medieval miniatures were one of the most important and original means of artistic expression, in which artists and illuminators made use of a diversified and rich palette that included many organic dyes, seldom found in easel painting. Created with the most luxurious and durable pigments, colors were a vehicle of beauty and mean- ing, 1,4–8 (Fig. 1). While the identification of most medieval inorganic pigments has become rather straightforward, 9–14 the characterization of organic dyes is a challenge that has been successfully addressed over the past few years by the development of advanced analytical techniques such as microspectrofluorimetry, fiber optic reflectance spec- troscopy (FORS), and surface-enhanced Raman spec- troscopy (SERS). 15–23 Combined, fluorimetry and FORS proved to be the most successful approach, 24,25 having the advantage of providing the best in situ analysis of colorants in the minute details of paintings in books of hours. Moreover, fluorimetry offers high sensitivity and selectivity, and the importance of sensitivity is clear when considering that the organic chromophores are usually present in very low concentrations because they may have faded or may have been applied as very thin coats over or mixed with an inorganic pigment or extender. 19,20 To improve the effect and usefulness of FORS and microspectrofluorimetry, it is necessary to test them in challenging and paradigmatic case studies, as the one proposed in this work. To achieve this goal and to disclose the complexity of red lake pigments found in the books of hours, 26–34 comparison with historically accu- rate reconstructions is essential. 35–37 Only by comparing the results obtained in the original manuscripts with medieval-accurate reconstructions, major progress in the understanding of the molecular structures of these complexes and their degradation mechanisms will be achieved. Indeed, artists’ materials available today do not reflect medieval technology, and therefore it is necessary to (re)produce the medieval colorants with materials and techniques as close as possible to the medieval ones. This will contribute to sustainable conservation and better access, as well as to a ‘‘social history of colors’’ and a better perception of medieval science and technology. 1–7 In the present work, we have selected and reproduced medieval recipes of the mid- 15 th century treatise O Livro de como se fazem as cores Received 12 August 2013; accepted 8 November 2013. * Author to whom correspondence should be sent. E-mail: mjm@fct.unl. pt. DOI: 10.1366/13-07253 434 Volume 68, Number 4, 2014 APPLIED SPECTROSCOPY 0003-7028/14/6804-0434/0 Q 2014 Society for Applied Spectroscopy