Beyond the blue color of lapis lazuli: compositional mapping in cross-sections of painting masterpieces

This abstract wishes to celebrate the memory of Prof. Austin Nevin describing the recent results obtained in a project aiming to establish an innovative analytical protocol for the analysis of micro-samples from paintings containing ultramarine blue pigment, derived from lapis lazuli using a combination of spectroscopic data generated by different analytical techniques (Raman, FTIR and Fluorescence) to gain compositional information and reveal conservation issues. The purpose was to overlap the information contained in each map, consisting of large spectroscopic data sets, using modern algorithms to enable a complete statistical and quantitative compositional evaluation. Preliminary and promising results have been achieved on some cross-sections from old master paintings of The Courtauld's Easel Painting. The present work has been supported by the Project IECR2212013 founded by The Royal Society of London (2021-2023) and by the European Project iPhotoCult (number: 10101132448).