SCIENTIFICALLY INVESTIGATING PICASSO'S SUSPECTED USE OF RIPOLIN HOUSE PAINTS IN STILL LIFE, 1922 AND THE RED ARMCHAIR, 1931

Ripolin - a popular French house paint - was used extensively by Pablo Picasso and some of his contemporaries. Its presence in particular artworks, however, has been difficult to confirm scientifically due to the chemical similarities between Ripolin and contemporary artist's tube paints, and the lack of knowledge about Ripolin paint formulations. This study compares data collected from a large reference set of historical samples of Ripolin and artist's tube paints with new analytical results from two Picasso paintings in the collection of the Art Institute of Chicago suspected to contain Ripolin: Still Life (1922) and The Red Armchair (1931). A variety of non-invasive and micro-invasive analytical techniques, including x-ray fluorescence spectroscopy, Fourier transform infrared spectroscopy, fiber-optics reflectance spectroscopy (350 to 2500 nm), Raman spectroscopy, optical and polarized light microscopy, and scanning electron microscopy (SEM) with energy dispersive x-ray spectroscopy, were used to analyze the paint samples. The results indicate that Still Life does not contain Ripolin, as it has pigments, such as vermilion and lead white, and extenders, such as barium sulfate, not used in French Ripolin house paints. On the other hand, The Red Armchair has paints matching closely with samples of Ripolin Blanc de neige, used alone and mixed with artist's tube colors.