Laser spectroscopy methods for an 18th century grisaille painting investigation

This paper presents a study regarding the quality of particular painting techniques - grisaille, black and white colors on thick paper, in case of an about 200 years old artwork, using exclusively two analytical laser techniques: Laser Induced Fluorescence (LIF) and Laser Induced Breakdown Spectroscopy (LIBS). The investigation aimed the identification of the type of white and black colors, and an other possible specific color (yellow or ochre) compounds (which were not allowed by this technique). The results proved again the known efficiency of each mentioned investigation technique, but also the conclusions that could be drawn from the correlated experimental data. The fast and efficient experiment took advantage of: i) double pulse LIBS technique that allows a more intense signal to be acquired, a reduced material consumption, the elimination of the matrix effect; ii) fast data mapping and characterization of critical points all over the painting using LIF scanning image.