Search

Funding Information: This research was funded by the Portuguese Science Foundation [Fundação para a Ciência e Tecnologia, Ministério da Educação e da Ciência (FCT/MCTES)], through doctoral programme CORES-PD/00253/2012, and PhD Grants awarded to Márcia Vieira [SFRH/BD/148729/2019] and Hermine Grigoryan [PD/BD/142886/2018]; Project STEMMA (“From singing to writing—survey on material production and routes of Galician-Portuguese Lyric”, PTDC/LLT-EGL/30984/2017); Polyphenols in Art—Chemistry and biology hand in hand with conservation of cultural heritage, PTDC/QUI-OUT/29925/2017, as well as "Pruevalo e veras ques çierto. Recetas y conocimientos de la sociedad medieval para el siglo XXI | "Try it and you will see thats true. Recipes and konwledges from medieval society to 21th century", PID2019-108736 GB-I00, Ministerio de Ciencia e Innovación. N. Teixeira and V. Otero acknowledge FCT for CEECIND/00025/2018/CP1545/CT0009 and 2020.00647.CEECIND, respectively; R. J. Díaz Hidalgo, posdoctoral UCO 2020, La producción documental y libraría al Ándalus siglos XIII XV, Plan Propio de Investigación de la Universidad de Córdoba; Associate Laboratory for Green Chemistry- LAQV financed by FCT/MCTES (UID/QUI/50006/2019 and UIDB/50006/2020) and co-financed by the ERDF under the PT2020 Partnership Agreement (POCI-01–0145-FEDER-007265). Publisher Copyright: © 2023, The Author(s). 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). publishersversion published more...

Funding Information: This research was funded by the Portuguese Foundation for Science and Technology [Fundação para a Ciência e Tecnologia, Ministério da Educação e Ciência (FCT/MCTES)], through PhD grants awarded to Márcia Vieira [SFRH/BD/148729/2019] and to Hermine Grigoryan [PD/BD/142866/2018], CEEC junior contract awarded to Paula Nabais (2021.01344.CEECIND), UIDB/EAT/00729/2020, UIDP/00729/2020; Associate Laboratory for Green Chemistry- LAQV financed by FCT/MCTES (UID/QUI/50006/2019 and UIDB/50006/2020) and co-financed by the ERDF under the PT2020 Partnership Agreement (PO-CI-01-0145-FEDER-007265); Glass and Ceramic for the Arts—VICARTE financed by FCT/MCTES (UIDB/00729/2020 and UIDP/00729/2020); Laboratory for Instrumentation, Bio-medical Engineering and Radiation Physics—LIBPhys financed by FCT/MCTES (UIDB/04559/2020 and UIDP/04559/2020). Calouste Gulbenkian Foundation grant on Armenian Studies (No. 269685) awarded to Hermine Grigoryan. Publisher Copyright: © 2023 by the authors. The illuminated manuscripts at the Gulbenkian Museum were produced in the 17th century, in scriptoria of the Armenian diaspora. In this work, we selected analytical methods that can be used in situ to study the colors of the illuminations. Scientific analysis based on fiber-optics reflectance spectroscopy in the visible and Raman spectroscopy has shown the use of a medieval palette based on inorganic pigments such as lapis lazuli, minium, vermilion, orpiment, indigo, two different greens (vergaut and malachite), lead white and carbon black. More importantly, in this context, it showed that the very important reds and pinks are possibly based on carminic acid. The painting technique is, however, different, as are the ways of painting the faces, hands, and vestments. The range of colors in the Bible and the three Gospel Books, enhanced by lapis lazuli blue and organic reds and pinks, demonstrates a desire to create exceptional illuminated manuscripts. publishersversion published more...

The Natural History and Science Museum of the University of Porto houses a collection of 45 models of fungi in papier-mâché from the 19th-century, which were used at the university until 2015 as didactic models. For the first time, the materials and techniques used in the production of a Boletus edulis model were studied (vernacular name: cep, porcini). These sculptures, made to life-size scale, are painted in colors similar to those of the represented species (white, brown, and light brown). They are fixed to a rectangular base, which is painted black, and to which moss has been pasted. To fully characterize each color, at the molecular level, a multi-analytical approach was used, combining energy-dispersive x-ray fluorescence spectroscopy (micro-XRF) with fingerprinting techniques of Raman microscopy (microRaman and handheld Raman) spectroscopy and microFourier transform infrared spectroscopy (microFTIR). The papier-mâché was prepared with a groundwood paper to which kaolin and a quartz-based material have been added to reinforce the structure. Raman microscopy also identified carbon black in it, which is possibly responsible for its grey color. The white color was unequivocally identified as lithopone by microRaman. This white paint was prepared in a proteinaceous tempera, with calcium carbonate having been identified as filler (by microFTIR). In the brown color, iron was identified by microXRF, pointing to the use of ocher, which was not possible to identify by microRaman and microFTIR. Regarding the black rectangular base, the moss was fixed using a collagen-based glue. The binding medium in this black is possibly a mixture of drying oil and protein. Again, XRF detected iron as the main element, but it was not possible to acquire a Raman spectrum due to the high fluorescence of the binder/varnish. Others, such as the writing inks, will also be discussed. The colors identified are in line with the best materials available for use by artists of that time. This new knowledge is fundamental to informing the choice of the best conservation strategies for the preservation of these extraordinary models. more...

Additional file 3: Details of pink vestments from the Ajuda Songbook.

Additional file 1: Brazilwood paint recipes, color paints, and color coordinates.

Additional file 2: Molecular data on brazilwood paints (infrared and Raman spectra).

Additional file 4: Fluorescence emission and excitation spectra acquired after 1 year.

The authors would like to thank José Alberto Ribeiro, director of Palácio Nacional da Ajuda, and Cristina Pinto Basto, coordinator librarian, for their generous support and rewarding collaboration. We also wish to acknowledge the Laboratory of Biopolymers—Centro de Investigación en Alimentación y Desarrollo, A.C (C.I.A.D., A.C.), Hermosillo, Sonora, México, for providing the samples of mesquite gum used in this work. This research was funded by the Portuguese Science Foundation (Fundação para a Ciência e Tecnologia, Ministério da Educação e da Ciência, FCT/MCTES) and co-financed by the ERDF under the PT2020 Partnership Agreement (POCI-01-0145-FEDER-007265). Project “Try it and you will see that is true”. Recipes and knowledge from Medieval society to the 21th century”, PID2019-108736GB-I00, Ministerio de Ciencia e Innovación. R. J. Díaz Hidalgo, posdoctoral UCO 2020, La producción documental y libraría al Ándalus siglos XIII XV, Plan Propio de Investigación de la Universidad de Córdoba; Publisher Copyright: © 2023, The Author(s). The Ajuda Songbook is an exceptional illuminated manuscript being the only surviving codex of Galician-Portuguese secular poetry; it was produced in the end of the thirteenth century, beginning of the fourteenth century. The diversity of colors accentuated by the presence of lapis lazuli blue and brazilwood pink, demonstrates the desire to produce a sumptuous manuscript. Pink is, in this context, a luxury color and its identification attests to one of the earliest known occurrences of brazilwood in artworks. Scientific analysis showed, for the light pinks, a different formulation from that found in fifteenth-century books of hours and from all historical reconstructions of these colors prepared to date. This knowledge was used to further expand a database previously built in our laboratory and applied to the characterization of pink shades in the Ajuda Songbook. Thirteen brazilwood recipes were selected from seven Medieval treatises and reference materials were prepared based on such historical information. Three types of colors were achieved, defined as translucent rose, rose, and red. The translucent rose was obtained from recipes where egg white is used for extraction, and no other additives are present; rose from recipes with calcium carbonate; and red from a wider range of recipes, in which these ingredients are not mentioned. These colors were then prepared as paints, and analytical results were thus compared with data from the light pinks seen in the Ajuda Songbook’s architectural backgrounds. We were able to reproduce the pink very well using infrared spectroscopy, identifying its main ingredients: calcium carbonate as filler; lead white as the pigment that produces light pink; and the binder as a polysaccharide with a fingerprint similar to mesquite gum. For the chromophore color, the application of chemometrics approaches to molecular fluorescence spectra highlighted a high degree of similarity with the paint reconstructions. publishersversion published more...

CORES-PD/00253/2012 PD/BD/105895/2014 SFRH/BD/148729/2019 PTDC/LLT-EGL/30984/2017 UIDB/50006/2020 UIDP/50006/2020 This work presents the first proof of concept for the use of molecular fluorescence signatures in medieval colours based on lac dye and brazilwood lake pigments. These two important medieval dyes were tested as markers using their UV–Visible emission and excitation spectra. These medieval paints had been previously fully characterized through a multi-analytical approach. In this work, molecular fluorescence spectra were acquired in manuscripts dating from 12th to 15th c., which were produced in monastic scriptoria or workshops. First, the spectral distribution and relative intensity of the emission and excitation spectra were discussed in detail by comparison with reference compounds, including reproductions of paints based on medieval technical texts. It was possible to group the spectra according to recipe specificities. Then, statistical methods (principal component analysis and hierarchical cluster analysis) were applied to the same fluorescence spectra and the generated clusters were compared with the previous ones. Principal component analysis was initially employed to eliminate redundancy in fluorescence data, so minimizing bias on the hierarchical cluster analysis results. Except for some misplaced spectra, the placement of samples per group was confirmed. The outliers resulted from either a poor signal to noise ratio or occurred because certain paints were unique, such as the colour produced by mixing lac dye and brazilwood, which was found in manuscripts from the Alcobaça monastic scriptorium. Previously, by using infrared or Raman spectroscopies, only lac dye could be detected. Notably, these paints compare well with a recipe that was reproduced from the text by Jean Le Begue, in which both dyes were required.[Figure not available: see fulltext.] publishersversion published more...

Additional file 1: Figure S1. Typologies of the manuscripts found in Portuguese collections. Table S1–S5. Microspectrofluorimetry and infrared data of samples from lac dye in medieval manuscript illuminations (12th–13th c.). Table S6. Microspectrofluorimetry and infrared data of lac dye reconstructions. Table S7. Infrared spectra. Table S8. Percentage of calcium carbonate. Table S9–S12. Microspectrofluorimetry and infrared data of samples from brazilwood in medieval manuscript illuminations (end of 13th–15th c.). Table S13. Microspectrofluorimetry and infrared data of brazilwood reconstructions. Figure S2. Scatter plot representing the first three scores from the PCA model used to produce the dendrogram for lac dye (Lac) and brazilwood (BW) based paints. Link to video in: https://www.dropbox.com/s/4vfyc63cjsvn7j1/Heritage Sci Nabais P_ Scatter plot.mp4?dl=0 . more...

UIDB/00749/2020 UIDP/00749/2020 This work provides new knowledge on natural yellows used in Iran. Seven biological sources were selected based on interviews with dye masters in Isfahan workshops (Iran). Delphinium semibarbatum, Eremostachys laevigata, Prangos ferulacea, Morus alba, Pistacia vera, Punica granatum, and Vitis vinifera are currently used in these workshops. Aiming to study the dye composition of wool samples dyed with the extracts of the selected biological sources and the changes induced by the dyeing procedures in the original chemical composition of the plant extract, raw materials and dyed wool (by us and in the workshops) were analyzed by HPLC–DAD and UHPLC–HRMS/MS. The main yellows for E. laevigata are luteolin-O-glycosides. In the other plant sources, the main chromophores are based on 3-O-glycosides of kaempferol, quercetin, and isorhamnetin. In pistachio hulls, myricitin derivatives were detected and we propose their use as markers. Generally, the solutions extracted from the wool displayed a higher amount of more polar compounds, but also a higher amount of aglycones. Importantly, the chromatographic profiles of the samples we prepared compared well with 17th c. yellows in Persian carpets, and therefore can be considered highly characterized references for the study of Persian yellowThis work provides new knowledge on natural yellows used in Iran. Seven biological sources were selected based on interviews with dye masters in Isfahan workshops (Iran). Delphinium semibarbatum, Eremostachys laevigata, Prangos ferulacea, Morus alba, Pistacia vera, Punica granatum, and Vitis vinifera are currently used in these workshops. Aiming to study the dye composition of wool samples dyed with the extracts of the selected biological sources and the changes induced by the dyeing procedures in the original chemical composition of the plant extract, raw materials and dyed wool (by us and in the workshops) were analyzed by HPLC–DAD and UHPLC–HRMS/MS. The main yellows for E. laevigata are luteolin-O-glycosides. In the other plant sources, the main chromophores are based on 3-O-glycosides of kaempferol, quercetin, and isorhamnetin. In pistachio hulls, myricitin derivatives were detected and we propose their use as markers. Generally, the solutions extracted from the wool displayed a higher amount of more polar compounds, but also a higher amount of aglycones. Importantly, the chromatographic profiles of the samples we prepared compared well with 17th c. yellows in Persian carpets, and therefore can be considered highly characterized references for the study of Persian yellows. publishersversion published more...

This study was supported by the Portuguese Science Foundation through the CORES Ph.D. Doctoral Programme in the Conservation and Restoration of Cultural Heritage with the Grants [SFRH/BD/52314/2013] and [PD/BD/105895/2014] and by Associated Laboratory for Sustainable Chemistry-Clean Processes and Technologies-LAQV which is financed by national funds from FCT/MEC (UID/QUI/50006/2016) and co-financed by the ERDF under the PT2020 Partnership Agreement (POCI-01-0145-FEDER-007265). The lack of comprehensive studies on silver paints in manuscripts is a handicap to new stabilization strategies and treatments. This work develops and tests a methodological approach for the study of the degradation of silver paints, at the molecular level, using as a case study a French Book of Hours dated from the 15th century from Mafra National Palace collection. In this paper, we show that the global equation commonly used by the cultural heritage community to describe the tarnishing of silver proves to be insufficient to understand the main factor causing its severe and extensive darkening in medieval illuminated manuscripts. This equation depicts the degradation of silver instantly with a sulphide containing species as H2S. Recent research has solidly proved that the first intermediate of silver oxidation is Ag2O. This theme will be presented in a forthcoming review. Within this framework, we selected four typologies of silver paints, all analysed by in situ techniques and four as microsamples; due to the very small size and fragility of the microsamples, new methods of sample preparation were developed and tested. The main research questions include: (1) understanding how silver-based colour are formed, disclosing its full stratigraphy; (2) define if the other compounds present, such as colour paints and the ground, may affect silver oxidation by stabilizing or accelerating it; (3) comprehend if it is possible to characterize the degradation products of silver paints with the methodology developed in this work, both in the bulk and at the interfaces between layers. Overall our results show that silver-based colours exhibit a complex stratigraphy that impacts its conservation condition. Further research at the molecular level is required on the correlation of the main components of the ground (binder and filler such as gypsum and calcium carbonate) and the paints that are applied as layers over or under the silver leaf. Our case studies have shown that both in situ analytical techniques and scanning electron microscopy with energy dispersive spectroscopy analysis in the microsamples, provide relevant information on the silver colour stratigraphy. However, the information obtained studying cross-sections is more accurate. We consider that the study of the degradation mechanism of silver in medieval illuminated manuscripts will require the combination of both approaches; in situ methodologies support the relevance of the data acquired on the microsamples. Microsamples studies will make possible the acquisition of data that is fundamental to understand the darkening of silver paints and this, in turn, is essential to develop informed and sustainable conservation policies. publishersversion published more...