TY - JOUR
T1 - New insights into brazilwood lake pigments manufacture through the use of historically accurate reconstructions
AU - Vitorino, Tatiana
AU - Melo, Maria João
AU - Carlyle, Leslie
AU - Otero, Vanessa
N1 - Sem PDF.
Portuguese Science Foundation, FCT-MEC (PTDC/QUI-QUI/099388/2008; PTDC/EAT-EAT/113612/2009; SFRH/BD/74574/2010; PD/BD/105902/2014)
REQUIMTE (PEst-C/EQB/LA0006/2014)
Netherlands Institute for Scientific Research (NWO)
Arts and Humanities Research Council (AHRC)
PY - 2016/9/2
Y1 - 2016/9/2
N2 - A multi-analytical approach for the study of brazilwood and its lake pigments was carried out based on historically accurate reconstructions. Recipes for brazilwood lakes from the fifteenth century technical text Livro de como se fazem as cores and the Winsor & Newton nineteenth century colourman's archive were reproduced and compared. Both primary sources allowed for the successful preparation of brazilwood lake pigments with colours that vary from light pink to dark red. The main steps and ingredients for the manufacture of these pigments were common in both sources, particularly the addition of Al3+ in the form of alum, and calcium carbonate (chalk). Reconstructions revealed that the latter acts as a pH buffer and filler, controlling the pH at which the lake pigment precipitates. The main difference between the two sources is that the nineteenth century recipes give the quantities for all ingredients, the precise temperatures and time, and achieved higher relative pigment yields (75% versus 45%). Full chemical characterisation of the reconstructions provided detailed information on the individual steps in the pigment manufacture and revealed that the presence of calcium sulphate dihydrate (gypsum) in the final pigment was a result of its formation in situ. Infrared, reflectance, and fluorescence spectroscopy proved to be essential and complementary techniques: while infrared was used to characterise additives and binders, reflectance and fluorescence data were fundamental for identifying the chromophore. The pigments and paints produced can now be used as standards for the identification and investigation of brazilwood lake pigments found in artworks.
AB - A multi-analytical approach for the study of brazilwood and its lake pigments was carried out based on historically accurate reconstructions. Recipes for brazilwood lakes from the fifteenth century technical text Livro de como se fazem as cores and the Winsor & Newton nineteenth century colourman's archive were reproduced and compared. Both primary sources allowed for the successful preparation of brazilwood lake pigments with colours that vary from light pink to dark red. The main steps and ingredients for the manufacture of these pigments were common in both sources, particularly the addition of Al3+ in the form of alum, and calcium carbonate (chalk). Reconstructions revealed that the latter acts as a pH buffer and filler, controlling the pH at which the lake pigment precipitates. The main difference between the two sources is that the nineteenth century recipes give the quantities for all ingredients, the precise temperatures and time, and achieved higher relative pigment yields (75% versus 45%). Full chemical characterisation of the reconstructions provided detailed information on the individual steps in the pigment manufacture and revealed that the presence of calcium sulphate dihydrate (gypsum) in the final pigment was a result of its formation in situ. Infrared, reflectance, and fluorescence spectroscopy proved to be essential and complementary techniques: while infrared was used to characterise additives and binders, reflectance and fluorescence data were fundamental for identifying the chromophore. The pigments and paints produced can now be used as standards for the identification and investigation of brazilwood lake pigments found in artworks.
KW - Brazilwood
KW - Fibre optic reflectance spectroscopy: FORS
KW - Historically Accurate Reconstructions
KW - Lake pigment
KW - Medieval
KW - Microspectrofluorimetry
KW - Winsor & Newton
KW - μ-Fourier transform infrared spectroscopy
KW - μ-FTIR
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U2 - 10.1179/2047058415Y.0000000006
DO - 10.1179/2047058415Y.0000000006
M3 - Article
AN - SCOPUS:84978471872
SN - 0039-3630
VL - 61
SP - 255
EP - 273
JO - Studies in Conservation
JF - Studies in Conservation
IS - 5
ER -