Differentiation with Raman spectroscopy among several natural ultramarine blues and the synthetic ultramarine blue used by the Catalonian modernist painter Ramon Casas i Carbó

Abstract

This paper investigates, using only Raman spectroscopy, the spectral differences among the synthetic ultramarine blue (J. B. Guimet) and three natural ultramarine blues (lazurites) corresponding to three lapis lazulis from different geographical sources (Chile, Afghanistan and Siberia). The synthetic ultramarine blue used as reference pigment is the identified in an artwork created around 1917 by the Catalonian modernist painter Ramon Casas i Carbó. This synthetic pigment is compared with the three natural ultramarine blues and, in his turn, the latter are also compared each other. In order to quantify the spectral differences, a rigorous methodology based on the Euclidean distance between homologue spectral segments (or intervals) has been developed and presented here.

Raman spectroscopy of minerals and mineral pigments in archaeometry

“…These features may be indicative of natural lapis lazuli from Afghanistan. De Torres et al tried to quantify the Raman spectral differences up to about 2000 cm −1 amongst the synthetic ultramarine blue and three lazurites corresponding to three lapis lazulis from different geographical sources (Chile, Afghanistan, Siberia).…”

Recent advances in linear and non‐linear Raman spectroscopy. Part IX

“…De Torres and co‐workers describe the Raman differentiation of several natural ultramarine blues and the synthetic ultramarine blue used by the Catalonian modernist painter Ramon Casas i Carbo. This synthetic pigment is compared with the three natural ultramarine blues and, in his turn, the latter are also compared each other . Dominguez‐Vidal and co‐workers carried out a comparative field and laboratory Raman study of decorated plasterwork in the Alhambra Field investigations were carried out in‐situ using a portable Raman spectrometer during a conservation campaign in a completely non‐invasive manner.…”

Applications of Raman spectroscopy in art and archaeology

“…The Raman spectral differences among the synthetic ultramarine blue (from the J. B. Guimet manufacturer) and three natural ultramarine blues (lazurites from different geographical sources: Chile, Afghanistan and Siberia) have been investigated by De Torres et al [45] The synthetic ultramarine blue used as reference pigment was identified in an artwork created around 1917 by the Catalonian modernist painter Ramon Casas i Carbo. The comparison of this synthetic pigment with the three natural lapis lazuli was performed using a home-made rigorous methodology based on the Euclidean distance between homologue spectral segments (or intervals).…”

“…The Raman spectral differences among the synthetic ultramarine blue (from the J. B. Guimet manufacturer) and three natural ultramarine blues (lazurites from different geographical sources: Chile, Afghanistan and Siberia) have been investigated by De Torres et al . The synthetic ultramarine blue used as reference pigment was identified in an artwork created around 1917 by the Catalonian modernist painter Ramon Casas i Carbo.…”