How Scientific Analysis Reveals the Technique and Materials of Three Allegorical Paintings by Veronese Part 1 of 3

Silvia Centeno, one of our research staff, is the expert on investigations in paintings, drawings, and illuminated manuscripts. She obtained her PhD in chemistry from Universidad de la Plata in Buenos Aires, Argentina, and she has been at the Met first as a research fellow and then on as a research scientist since 1995. She has contributed with articles to numerous exhibition catalogs, and you can see her works ranging from artists such as Van Gogh and objects including photographs, paintings, and illuminated manuscripts like the Beaux-Arts of the Duc de Berry. She has an important contribution to our research in the United States. You've seen the Raman spectrometer that Dr. Ernst is using so well, and Silvia was the first scientist in the museum in the United States to introduce the technique with great advantage for our work. Please welcome Silvia Centeno. Thank you, Marco, and good afternoon. Thanks for coming, and it's really a pleasure to be here. First of all, I want to say that this was teamwork, and these are the colleagues I work with. Dorothy Mann, a paintings conservator in this museum, who I think is in the audience. She also cleaned the surface of the paintings in preparation for the exhibition. Mark Wiebke, a research scientist in our museum, who's a specialist in ancient glass. Andrea Bayer, curator of European paintings, and Seybert Salomon, who at the time of the project was an Andrew W. Mellon Curatorial Fellow at the Frick Collection, and is now a curator at the Dulwich Picture Gallery in London. We examined these three allegorical paintings by Paolo Veronese, Mars and Venus, United by Love, in the collection of this museum. The choice between virtue and vice and wisdom and strength from the Frick Collection to aid in understanding the historical relationship among them and to gain further insight into Veronese materials and techniques. I hope I can show how scientific analysis contributed to explore the technique Veronese used to achieve certain color effects and to shed new light into problematic issues such as whether virtue and vice and wisdom and strength have been created as a pair, have been created by Veronese to be seen together, or whether some paint passages were meant to look the way they do today or their appearances are the result of a change that has occurred over time. In an article published in 1913 in the magazine Art in America, the art historian Detlef von Hadern proposed that the three allegories, Mars and Venus, virtue and vice, wisdom and strength, together with Mercury, Herce and Aglaurus, now in the collection of the Fitzwilliam Museum in Cambridge, have been created as a group for Emperor Rudolf II, likely after Rudolf's coronation in 1576. This hypothesis proved to be an influential one and as a consequence the original commission of the four paintings has been a matter of art historical debate for the last almost last 100 years. Von Hadern did not consider the four paintings as a meaningful portrait. He thought that virtue and vice and wisdom and strength were a pair, had been created to be seen together, and that Mars and Venus and Mercury were companion pieces. It is unlikely that Mars and Venus and Mercury were created to be seen together. Mars and Venus is much smaller, the styles are quite different, and also it is difficult to imagine how the iconographies would weave together. On the other hand, virtue and vice have similar sizes, they are very similar in facture, it means that they have been built up in similar ways. They both explore themes that have to do with virtuous living, though it's again difficult to understand how the two would weave together. The exhibition Veronese's Allegories, Virtue, Love and Exploration in Renaissance Venice, that took place at the Frick between June and April 2006, was the first display to fully address the issues of the original commission, dating and provenance of the paintings. Unfortunately, Mercury, Herzen and Glaurus could not join the exhibition due to loan restrictions, but this was the first time in more than 200 years that Mars and Venus, virtue and vice, and wisdom and strength had been seen together, and this presented us with an unparalleled opportunity to closely examine the paintings and compare them as it had not been done before. To examine Veronese's materials and techniques, we remove microscopic samples under the microscope. Samples removed by conservators and scientists working in museums are usually very small, in the order of one-tenth of a millimeter, and they're removed from areas where there's already a loss or a crack on the painted surface that does not induce further damage. These samples are often mounted as cross sections in a synthetic resin and polished. You have here the sample removed from this dark area in the sky in Mars and Venus. You have at the bottom of the cross section the ground preparation. This is the first layer that is applied right over the canvas support, and then you have the different paint layers that the artist used to build up the different passages. So examination and analysis of these samples gives us information not only on the artist's working practice and the materials used, but also on whether these materials have changed over time. In the case of the samples that we removed from the three allegories, we used two complementary microanalytical techniques, Raman spectroscopy and energy dispersive x-ray spectrometry, and Professor Ernst already described Raman spectroscopy. It gives us information on the Raman spectrum as a fingerprint of the material. This is one of the Raman spectrometers in the museum laboratories. Samples are placed in the stage of the microscope and spectra are recorded in the different paint layers. What I want to stress here is that what makes the technique very, very powerful in addition to its molecular specificity is its spatial resolution. We can get a spectrum from a particle as small as three microns in diameter without interference from the surrounding particles. So to give a sense of the dimensions here, these paint layers are in the order of 10 to 15 microns. So we can easily focus within the paint layers, get their composition without interference from the layers that lie above or beneath. We complemented these measurements with scanning electron microscopy energy dispersive x-ray spectrometry, SEMEDS for short. The technique gives us information on the elemental composition of the materials, what elements make up the materials. Analyses are done in an electron microscope, so spatial resolution is very, very high. Again, we can go to very small particles, get their elemental composition without interference from the surrounding particles. So now, back to the paintings, we're going to start by comparing Wisdom and Strength and Butron Weiss. As I said, both paintings have similar sizes. They appear to have been built up in similar ways, and we'll see now how similar or how different they are. We'll start by looking at the canvas supports. Butron Weiss is painted on two vertical strips of a fine plain wood canvas, and you see more clearly the join between the two vertical strips here in the x-ray. I draw this red line through the paint, through the surface of the painting, so you have a sense of where it goes through. The piecing out of a canvas support at the time was necessary because the maximum width of a standard loom was about one meter. So Butron Weiss is painted on a fine plain wood canvas, but on the other hand, Wisdom and Strength is painted on a much rougher canvas, made out of three vertical strips, a larger strip to the right and two smaller strips to the left. So the fact that the two canvas supports are different is indicating that these two paintings were not created as a pair. While other artists, such as Sintoretto, used different canvas supports for paintings in the same cycle, after all, a wide range of canvas was available in Venice at the time because of the manufacture of sails for ships. This does not seem to be the case with Veronese.