The article focuses on the analysis of organic lake-pigments in a mid-16th century illuminated Antiphonary using Fiber Optic Reflectance Spectroscopy (FORS) and chemometric approaches. Researchers from the University of Évora in Portugal conducted the study, aiming to understand the pigments used in the manuscript’s illuminations. They analysed historical paints and reconstructions of madder, brazilwood, and cochineal lake paints to interpret the influence of binders and pH sensitivity on colour discrimination.
The study revealed that cochineal was crucial in producing reddish-to-pink hues in the manuscript, with different shades achieved through acid-basic equilibrium. The production of organic lake pigments involved grinding the pigments with binders and applying them to parchment. Colorimetric analysis was performed with a spectrophotometer, ensuring measurements under 2.5 seconds with a 3 mm aperture spot size.
FORS analysis was conducted using a compact spectrometer with specific settings for exposure, scans, and spot size. Micro-sampling and chromatographic analysis confirmed the presence of cochineal in the pigments. The combination of FORS spectroscopy and Principal Component Analysis (PCA) provided valuable insights into the organic pigments’ composition and the binder’s influence on colour variations.
The study’s findings contribute to understanding the materials and techniques used in mediaeval and Renaissance illuminations, shedding light on the artistic practices of that era. Overall, the research showcases the significance of analytical methods in art historical studies, offering a chemometric approach to unravel the mysteries of historical pigments and their applications in illuminated manuscripts.
