Identification of protein binders in construction sites Cuban pictorial art

Abstract

In this paper were implemented microanalysis methodologies by histochemical analysis, and infrared
spectroscopy to determine the nature of the binder in paintings and Gas Chromatography (GC) coupled to
Mass Spectrometry (MS) for identification of protein binders of common use in tempera technique with the aim
of having these methods as part of the identification of artistic materials in Cuban cultural heritage carried out by
Archaeometry Laboratory of Havana city’s Historian Cabinet. The methodologies implemented were evaluated
using model samples of traditional painting techniques with variable protein binder: yolk, egg white, casein, nut oil
and animal glue; ageing for 5 years. The models samples were correctly identified. It was determined the interference
of pigments with the presence of nitrogen by histochemical analysis with Amido Black dye. IR spectroscopy
technique allowed to differentiate between oily and mixed (oil plus protein) techniques and tempera with yolk.
Oily technique was identified in wall paintings of the New San Francisco church (xix century) and the Obrapía
House (xvii century) and the technique of tempera with animal glue in the polychrome of the xviii century which
represents St. John the Evangelist belonging to the San Juan de Letrán church