Picasso, a new study on differences in degradation of his paintings

A team of international researchers has conducted the first study to consider mechanical degradation issues in paintings by Pablo Picasso (Malaga, 1881 - Mougins, 1973) using an analytical and diagnostic approach. The study considered the four paintings that Picasso made in Barcelona in 1917 inspired by the Ballets Russes and using very similar materials: seven pigments, siccative oils, animal glue, and canvas. The paintings remained in Picasso’s family home until 1970, when they were donated to the Museu Picasso in Barcelona. A century after it was made, one of the four works,Hombre sentado (“Seated Man”) appears in a precarious state of preservation, worse than the other three in the series. Experts note many cracks, technically called “surface cracks.” The museum thus decides to restore the work and figure out why those differences between works that were in many ways similar and had shared a century in similar condition.

Thus was born the Promesa project (Study of the mechanical and dimensional properties of commercial paint films), coordinated by Laura Fuster-Lopez, professor of Conservation at the Universitat Politècnica de València and recently concluded with the publication of the results in the scientific journal SN Applied Sciences. The Universidad Politècnica de Valencia, Ca’ Foscari University of Venice, the Museu Picasso in Barcelona, as well as the CNR-Istituto Fisica Applicata “Nello Carrara,” the Escuela de Conservación y Restauración de Bienes Culturales de Aragón, the Royal Academy of Fine Arts of Denmark, and Queen’s University in Kingston, Canada.

Picasso’s four 1917 works proved to be the perfect testbed to begin investigating the correlation between the pictorial materials used by the artist and their actual condition. Using a multi-analytical approach and cutting-edge technology, the team ’s scientists studied each layer to extract the information hidden from view.

“The project,” says Laura Fuster-Lopez, “focused on the combined study of chemical composition and physical-mechanical degradation mechanisms that occur in modern and contemporary artworks. Since not all problems have a common cause, and since our artworks continue to deteriorate silently even under controlled storage and exhibition conditions, it is necessary to understand what aspects inherent in the composition of the materials used by artists may be the cause of their instability over time, in order to adapt preventive conservation measures in our collections.”

“The analyses carried out,” explains Francesca Izzo, a researcher in Chemical Sciences for Cultural Heritage at Ca’ Foscari University Venice and an expert in 20th- and 21st-century paintings, who focused on investigations of the painted layers and the layers of the pictorial preparation, “highlight that Picasso painted with oil paints containing both traditional linseed oil and less siccative oils such as safflower and sunflower oil. In one case, then, we speculate that the artist experimented with the use, not yet in vogue in 1917, of semi-synthetic paints. The canvases used by the artist were made of cotton, on which Picasso spread two different layers of preparation: one obtained with animal glue, the other with siccative oil. In both cases mixed with different pigments (white lead, barite, zinc oxide, etc.). In addition, it is interesting to note the presence of the so-called ’metal soaps,’ compounds formed by interaction between the binder and some ions released by the pigments that can cause very visible damage, both at the level of aesthetics and at the level of chemical and mechanical stability.”

The results obtained were combined with visual examination of the cracks and mechanical problems in the paintings to establish hypotheses about the differences in degradation. This is one of the first times that an approach based on noninvasive documentation techniques, chemical and physical analysis, and observations of mechanical damage has been taken to provide insight into the possible contribution each layer has on the observed degradation. It emerged that interactions between pigments and binders may have made the pictorial films more or less prone to degradation. The same was observed in the layers under the pictorial film: different preparation thicknesses, different pigment-binder interactions, and other minor differences that may have caused a different reaction to environmental conditions.

The in-depth study of the case has raised new questions and insights for new research. Scientists are trying to discover the role of possible “migration” of materials between the paint and preparation layers. With the new scientific results in hand, Reyes Jiménez de Garnica, director of the Preventive Conservation and Restoration Department of the Museu Picasso in Barcelona, will be able to refine strategies for preventive conservation and evaluation of the conservation conditions (particularly the role of humidity) and exposure of the works.

Image: Pablo Picasso, Hombre sentado (1917; oil on canvas, 104 x 54 cm; Barcelona, Museu Picasso)

Picasso, a new study on differences in degradation of his paintings

Warning: the translation into English of the original Italian article was created using automatic tools. We undertake to review all articles, but we do not guarantee the total absence of inaccuracies in the translation due to the program. You can find the original by clicking on the ITA button. If you find any mistake,please contact us.