Red lakes from Leonardo's Last Supper and other Old Master Paintings: Micro-Raman spectroscopy of anthraquinone pigments in paint cross-sections

• The analysis of red particles in paint cross-sections from Leonardo da Vinci's Last Supper, Masolino da Panicale's wall painting Beheading of St. John the Baptist in Castiglione Olona, Tintoretto's The Discovery of the Body of Saint Mark and Paolo Veronese's Supper in the House of Simon has been carried out with micro-Raman measurements. Subtracted shifted Raman spectroscopy methods have been employed to resolve the signals in the presence of fluorescence. Taking advantage of the vibrational assignments based on recent ab initio calculations of aluminum-complexes of anthraquinones, the approach allowed the discriminate between anthraquinone dyes and lakes based on kermesic and carminic acids present in the studied samples for the first time without heavy sample treatment. (C) 2019 Elsevier B.V. All rights reserved.

Ämnesord

NATURVETENSKAP  -- Kemi -- Fysikalisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Physical Chemistry (hsv//eng)

Nyckelord

Raman microscopy

Organic pigments

Cochineal

Kermes

Carmine

fluorescence rejection

organic colorants

cretan school

natural dyes

identification

scattering

spectra

sers

extraction

alizarin

Spectroscopy

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