Characterization of Sorolla's gouache pigments by means of spectroscopic techniques

• Gouache pigments have been identified by portable EDXRF spectrometry.
• OM and SEM-EDX analyses reveals the structure of the paint layer.
• Sorolla's sketches for the Vision of Spain have been analyzed for the first time.

This paper presents the characterization of the Joaquín Sorolla's gouache sketches for the oil on canvas series “Vision of Spain” commissioned by A. M. Huntington to decorate the library of the Hispanic Society of America in New York. The analyses were focused on the identification of the elemental composition of the gouache pigments by means of portable EDXRF spectrometry in a non-destructive mode. Additionally, SEM-EDX and FTIR analyses of a selected set of micro-samples were carried out to identify completely the pigments, the paint technique and the binding media. The obtained results have confirmed the identification of lead and zinc white, vermillion, earth pigments, ochre, zinc yellow, chrome yellow, ultramarine, Prussian blue, chromium based and copper–arsenic based green pigments, bone black and carbon based black pigments, and the use of gum arabic as binding media in the gouache pigments.