How to remove unoriginal varnish and overpaint from a 17^th-century oil painting?  Step 1: Obtain a graduate degree in art conservation; Step 2: Carefully perform cleaning tests using a range of organic solvents, gel systems, and aqueous methods; Step 3: Choose a system that can be safely administered without causing harm to the underlying original paint layers.

The removal of degraded coatings and discolored overpaint has long been a  controversial topic in the history of restoration.  Today, conservators have access to a wide range of materials and solvents and are equipped with a substantial background in chemistry.  Restorers of the past were limited by what they had access too, which unfortunately included the use of harsh chemicals and concentrated acids and bases (such as lye and ammonia).  Modern professionals have access to a wide range of materials and solvents, and conservators are armed with a substantial background in chemistry.

     Concepts such as pH, conductivity, and solubility are always taken into consideration during testing.  Problematic pigments and other components can also be sensitive to different cleaning procedures.  So PLEASE think twice before grabbing your bottle of Windex® when you are thinking about cleaning a painting!!

The cleaning process has really involved two major steps, removal of the yellow varnish followed by the removal/reduction of discolored overpaint.  Blues, whites, and lighter tones tend to suffer the most dramatically when covered with a thick, yellow veil of varnish as demonstrated in Figure 1.  Below the varnish, the conservators also encountered multiple layers of restoration “glazes” that had been hastily applied across the entire surface.  Several other figures had been treated in a similar manner during previous restoration campaigns, notably the standing solider on the left side ofthe painting.  In Figure 2, it is possible to get a sense of how broadly the overpaint had been applied; in many areas the original drapery pattern and the folds of the cloak were entirely hidden or poorly misinterpreted by past restorers.

While some areas possessed large amounts of varnish and overpaint, others simply suffered from blanched varnish.  “Blanching” occurs when the varnish has become significantly degraded and no longer exists as a continuous film.  Microscopic air pockets begin to form within the film and between the varnish and the paint.  This makes it difficult to read the paint beneath as the varnish is no longer effectively saturating the surface.  Conservators decided to leave small areas of the blanched varnish intact for students, scholars, and visitors to get a sense of how degraded the varnish had become (see Figure 3).   By December, the conservation team had been able to successfully clean the bottom half of the painting, moving onto the top half after the New Year.

Amanda and Kristen discuss sampling locations with Emily taking notes.

The chemistry team has been busy this past month sampling and preparing cross-sections for analysis from The Triumph of David. As mentioned last time, x-ray fluorescence (XRF) is a technique that allows us to get a broad overview of what inorganic elements are present in a particular area of a painting. Usually, XRF can be  incredibly useful in getting an idea of what pigments may be present in the area being analyzed. However, since the x-rays can penetrate all the way through to the canvas of the painting, we have no way to tell in which paint layer the detected elements are present by XRF alone. In order to determine which layer the pigment is located, we need to take a sample and prepare a cross-section. Cross-sections are beneficial for our research in that they not only allow us to visualize the different layers of paint present in an area, but also, with new developments in microscopy, we can determine which inorganic materials and binding materials are present in each layer as well.

Example of a cross section taken from King Saul’s red cloak.

Sampling  from a 17th century painting isn’t quite as scary or taboo as it might seem at first. While the removal of anything original to the painting is not ideal, sometimes a sample is necessary in order to get the most accurate idea of the make-up of the painting. Conservators and scientists will take micro-samples, often no bigger than the period at the end of this sentence.  We micro-sample from areas of pre-existing loss: meaning areas where the paint has already started to flake away. In the case of The Triumph of David, there were innumerable areas of loss from which we could sample. Obviously, we couldn’t and didn’t want to sample from every area of loss; so, we chose our sampling locations partially based on where the XRF gave intriguing results and partially in areas of interest to the conservators–namely, areas that appeared to be heavily overpainted or areas where it was difficult to distinguish pentimenti from later restoration campaigns. The micro-sample is then embedded in a plastic and cut and polished until the cross-section is exposed as in the figure above.  This single exposed cross-section can be examined using a vast array of microscopic techniques which will be expounded upon in future blogs.

Sampling location of aforementioned cross section

This sample in particular was taken from the red cloak on King Saul, and the image above was taken at 80x magnification. We took a sample in this location because we were curious to see if Saul’s cloak had been repainted and also to see if the red pigments matched other red pigments seen throughout the painting. As shown in the full size cross section above, there are obviously very different paint layers present in this one cross-section. The bottom two tan/brown layers are called ground layers. A ground layer is present in any painting and serves as a preparatory layer, creating a uniform surface on which to paint. Layer 1 appears to be made with less finely ground particles than layer 2, as you can see from the bigger particles present in layer 1. This means that layer 1 provided an initial ground layer to size the canvas, whereas the second layer created a uniform paint surface. Layer 3 is the first intentionally pigmented red paint layer that provides the coloring for Saul’s cloak. Finally, Layer 4 is the 1956 re-varnish present on the entire painting that the conservators are actively removing. Varnish serves the purpose of bringing more saturation to a painting as well as providing protection for the paint underneath. It is this varnish that has degraded over the years and has accumulated dirt which can be seen in the cross-section.

Cross section taken from the left side soldier’s overpainted red cloak.

However, not all cross sections are this straight forward to interpret. A good example is the cross-section, shown to the right, taken from a soldier’s red cloak, an area that may have been re-painted more than once during previous restoration campaigns. Cross sections, especially with a painting of this age and indefinite history, can be incredibly complex and often yield more questions than answers. Frequently, it becomes difficult to tell which layers are original and which are from subsequent restoration attempts. Cross sections like the one above require more than just a visible light micrograph in order to fully interpret the image. Techniques that go beyond what our eyes are capable of seeing, such as fluorescence microscopy and scanning electron microscopy, are incredibly useful as they can help us understand the binding materials and inorganic pigments used in each layer. So stay tuned as we keep unraveling the mystery of Pietro da Cortona’s The Triumph of David.

Until then, Ciao!

-Kristen, Amanda, and Anthony.

Very little is known about the painting: not when or why it was painted, where it was originally located (perhaps Castle Nemi, perhaps not?), or even who exactly painted it. A large part of my research will be to unearth key stylistic and technical practices of Pietro da Cortona that will solidify the attribution and help us to situate the painting within the artist’s oeuvre. Additionally, better knowledge of Cortona and his workshop’s practices helps us reconsider what the painting originally looked like.

It is already known that Cortona had a large workshop, meaning that at any given time he had several apprentices learning from him by doing much of his work. Unless otherwise dictated in the contract, an artist would make the preliminary sketches and plans for a commission, hand it over to his apprentices to do much of the work and only come in to contribute to the more important figures. In the case of Villanova’s work, it is currently assumed that Cortona would have worked on Goliath’s head and possibly David and the central figures that support Goliath’s head on the pike. In ascertaining how he managed his workshop for other commissions, I will be able to develop a hypothesis of how much apprentices worked on the painting and which apprentices would have been studying with Cortona at the time. Doing this will aid the conservators should they come across areas that do not match stylistically with the rest of the painting.

Pietro da Cortona, The Triumph of Divine Providence and the
Fulfillment of her Ends under the Papacy of Urban VIII,
Fresco, 1633-1639, Palazzo Barberini, Rome

Pietro da Cortona is best known for his frescoes and architecture (such as the celebrated fresco pictured here), which is where scholars have typically focused their attention. Using these sources causes problems because fresco requires a different skill set and approach to preparations than oil painting does. That being said, I can still investigate stylistic choices and information about who worked with him during these projects through articles and books that discuss his frescoes. With such limited sources, I have to get creative. For example, there is only one comprehensive book on Cortona, and it’s in Italian,which I fortunately can read. In this book, in fact, I discovered that he painted a Life of David cycle for the Sacchetti family, one of his major patrons. One of them, Triumph of David, is very similar visually to our Triumph of David, with a few compositional changes. This is a recent discovery, so I am still in the process of searching for other references to this project.

Falvey Memorial Library serves the four colleges of the Villanova University community. The Villanova School of Law has its own library. The University’s original library building, commonly referred to as Old Falvey or the Old Falvey wing of the Library, is actually Falvey Hall, a structure built in the 1940s. The newer library building, Falvey Memorial Library, was built in the 1960s. It sits adjacent to Falvey Hall aka Old Falvey, and the two buildings are intertwined, but do not communicate very well with one another. The floors do not align for one thing, and for security purposes the public needs to exit the one building to enter the other.

One of the greatest features of Falvey Hall, which has its collegiate gothic façade facing the Mendel Green, is a high ceilinged reading room. After the new library building was opened, the reading room in Old Falvey served several purposes. The large painting on canvas donated to the University in the 1950s was mounted in the reading room probably because it was a large enough space to accommodate the 12×19’framed oil painting. Unfortunately when the reading room stopped being used for public functions, the painting went generally unseen. The conservation campaign now underway is an exciting venture to restore the painting, and reopening the reading room to the public means visitors can see the painting while conservation takes place. Unlocking the reading room is also a way for Falvey to add additional 24/7 study space for Villanova students.  A major next step is to find funding for refurbishing the reading room not only to upgrade the environment for student use, but in order to create a more fitting and hospitable location for the Cortona painting.

A Learning Commons in Falvey was dedicated in February of 2012. This revitalization of Falvey’s second floor was a significant step forward in the overall renovation of the Library. It is a part of a larger plan to renovate the entire Falvey complex. The renovation and refurbishment of the reading room will be another major step. The ultimate step is to establish an atrium that would be cut from the Old Falvey book stacks and would connect the reading room in Falvey Hall to the main part of Falvey Memorial Library in a dramatic and grand way. The hope is that the Learning Commons will have an entrance and staircase into the reading room and that the reading room will be open to the atrium. The Cortona painting will remain in the reading room and perhaps, if they too can be restored, the other paintings donated to the University by Princess Eugenia Ruspoli could hang salon style alongside the “Triumph of David.” These plans are all contingent on fundraising led by colleagues in University Advancement.

In fact, transforming Falvey into a 21st century Library facility is one of several priorities of the recently launched comprehensive campaign at the University. A timeless focus on the needs of the academic community of Villanova is at the core of Falvey Memorial Library. In the 21st century this includes providing spaces that allow the mind to think and the imagination to create – where the student can focus on her studies, information is transformed into knowledge, and library research is accomplished – while at the same time serving as a generative intellectual environment which includes inspirational spaces. The renewal of the classic reading room space, home to a truly awe inspiring work of 17th century art and which is connected in an integrated fashion with the Learning Commons as well as other traditional library functions, is to have a place at the heart of Villanova’s campus which embodies the engagement of the whole student, in mind, body, and spirit.

by Darren Poley, Interim Library Director

Kristen Watts using XRF to analyze The Triumph of David

As The Triumph of David conservation project gains momentum, we, the chemistry team, have been studying the materials used in the painting. Conservation science is considered science in the service of cultural heritage and is a field of study that most science majors don’t even know exists.  Conservation scientists are interested in the chemistry of artistic materials and techniques and how they age in an artwork’s environment.   The proliferation of high-powered analytical instrumentation has made it possible to analyze historical objects with in-depth, non-destructive techniques. Our role in the conservation team is to provide data to conservators that can identify the materials used by the original artists as well as the materials used during subsequent restoration campaigns (a campaign refers to restoration efforts separated by time).  We are also hoping to provide the art historians with technical information that may help with dating and understanding how Pietro da Cortona and his workshop painted this rare, large format, oil-on-canvas painting.  Ultimately, we would like to provide a scientific answer as to why the varnish and the areas of obvious overpaint have darkened and deteriorated so quickly since the most recent restoration campaign in 1956. At this moment, we are busy trying to identify the pigments present in the painting as well as which paint layers are original and which are restoration.

Inorganic pigments, like verdigris or vermillion, can often be identified utilizing x-ray fluorescence (XRF) and scanning electron microscopy paired with energy dispersive x-ray analysis (SEM-EDX). During the past few weeks, we have been focusing our work on XRF as well as optical microscopy of cross-sections that have been taken, but today we are going to focus on some of our XRF results.

Schematic of XRF process

XRF is incredibly useful in conservation science not only because it’s nondestructive but also because portable, hand-held instruments are available, meaning that the instrument can be brought to the painting instead of bringing the painting to the lab where the instrument resides. XRF utilizes high energy X-rays to eject inner shell electrons from an element. The outer shell electrons will then fill the electron hole, releasing an x-ray photon in the process. This photon release is known as fluorescence and the particular energy of the released photon is specific to each element. Because of this specificity, we can use XRF to help us identify inorganic pigments in areas of interest. (For a more in depth look at the XRF mechanism of action, see here)

XRF spectra of the yellow shirt and the red robe on the soldier.

In the case of the soldier’s red robe (as seen in the photo at the left) we found a signal for mercury (Hg), indicating that the red color is probably due to a vermillion (mercury sulfide) pigment. There was also a large signal for lead (Pb) but this signal is found throughout the painting as it is caused by a lead white containing ground layer. His yellow shirt, on the other hand, showed signs of chromium(Cr) and barium (Ba) which would indicate a more modern chrome yellow (post 1800) or lemon yellow (post 1830) paint, thereby indicating that one of the paint layers originates from a more modern restoration campaign.

As mentioned previously in the Metigo map blog post, there are a lot of areas with heavy overpaint present as well as several restoration campaigns. By using XRF to monitor the presence of zinc (Zn), we can assist the conservators in tracking the removal of the restoration materials. Currently, zinc is suspected to be a component of the varnish or in a slightly pigmented glaze from a previous restoration. We suspect this because we see zinc disappear significantly with varnish removal, as seen in the image below, comparing the uncleaned overpaint (red), cleaned but still overpaint (green), and cleaned without overpaint (pink) all on a soldier’s leg in the painting. The spectrum corresponding to the uncleaned overpaint shows a moderate zinc signal, whereas zinc is not detected in the spectrum corresponding to an area of overpaint with just the varnish removed and the spectrum corresponding to a completely cleaned area.

Comparison of uncleaned overpaint (red line), cleaned overpaint (green line), and totally cleaned (pink line) areas present in a soldier’s leg

Because XRF simultaneously examines all the layers of the painting from the ground, paint layers, over-painted layers, and varnish, we can’t tell exactly in which layer the pigment is present by XRF alone. However, this XRF data is useful when determining where to micro-sample the painting to get layer-specific pigment information through techniques such as SEM-EDX and fluorescence microscopy, which you can read about in later posts. We are just beginning to unravel some of the mysteries surrounding this painting and our team is learning more every day.

Until next time, Ciao!

Anthony, Amanda, and Kristen.

This week we have been examining the painting from a digital perspective. The conservation team was fortunate enough to borrow a copy of Metigo MAP software produced by the German company,  fokus GmbH Leipzig (through a collaboration with University of Delaware).

Screenshot of Metigo MAP Software

Metigo MAP is a program used in the fields of architectural planning and art conservation that helps document and diagram conservation issues and the condition of a work of art or artifact.  Documentation is a task performed by all professional conservators before, during, and after treatment. Keeping meticulous records is not only an ethical obligation of our profession (AIC Code of Ethics), but it also serves as a reference during treatment. Over the next two years multiple interns will assist on this project, and the records that we are creating now will help inform new team members. The documentation also is a preservation tool and helps relate the complete history of this painting. Although we are removing overpaint from previous restoration campaigns, it is important to record what is being removed so that the public can understand exactly what this canvas has gone through.

We learned more about the applications of Metigo MAP from conservator Emily MacDonald-Korth’s talk, “Speed, precision, and a lighter load: Metigo MAP 3.0, a great advancement in condition mapping for large-scale projects, at the American Institute for Conservation’s 39th Annual Meeting.  Metigo MAP is especially useful for large-scale projects such as this one.

Sometimes conservators will draw a diagram by hand, but with something this large, suffering from multiple condition issues, a digital diagram is clearer and more efficient. Metigo MAP also rectifies the image that we import into the software so that all markings and outlines on the diagram are to scale and can be measured in the program. Therefore, we will be able to calculate the total area of the overpaint present once we have outlined it all on Metigo MAP.

Another key feature of the program is the ability to divide condition issues into separate mapped groups, like layers in Adobe Photoshop. This allows us to view all mapped issues at once or view a map of only one condition issue at a time. As we continue to clean the painting, we are revealing more areas of damage and loss that were previously concealed with overpaint. We plan to import a mid-treatment photograph of the painting into Metigo MAP and diagram any newly uncovered damage post-cleaning.

We are also using this project to help build a template in the Metigo program for symbols of common conservation issues and damage that can occur to a painted surface. Then, for future projects we can import the template and Metigo diagrams will be easy to compare because they will utilize the same legend.

In-progress Diagram of Condition Issues

Take a look at what we have recorded so far on our in-progress diagram, which clearly demonstrates the vast areas of overpaint that now obscure the artist’s original paint layers.  This diagram helps clarify and summarize what we are seeing everyday up close during treatment. The shaded purple zones indicate localized areas of overpaint that were most recently applied to the painting (presumably within the last 100 years). The blue hatching is used to map areas that were vastly overpainted during an earlier restoration attempt. The yellow lines are areas of paint loss while the red outlines demarcate areas of tenting paint. Tenting occurs when the canvas and/or earlier layers of paint expand and shrink deferentially due to gradual changes in relative humidity. These changes cause tension to build in the paint film, and eventually the paint gives way and cleaves into a peak that visually resembles a tent-like formation. Finally the white lines show where a previous application of varnish was not applied evenly and created drips.

Welcome to our weekly blog detailing the conservation treatment of Pietro da Cortona’s “Triumph of David”, a large-scale oil on canvas that currently resides in “Old Falvey,” Falvey Memorial Library’s original wing. The painting first came to the University in 1956, donated by the late Princess Eugenia Ruspoli who inherited the artwork from her late Italian husband, Prince Enrico Ruspoli. For much of its life, the “Triumph of David” hung within the walls of Castle Nemi. The castle sustained significant damages during World War II which may partly explain the current condition of the painting. Pietro Berrettini da Cotrona was perhaps best known for his work as an architect, however the artist and his workshop executed several exquisite fresco cycles in addition to a number of canvas paintings. As only a hand-full of Pietro’s canvas paintings can be found in museum collections, the University is make a concerted effort to restore the artwork and promote collaborative research amongst art historians, conservators, and scientists. More information can be found in the recent press release.

Villanova now joins a hand-full of cultural institutions and conservation laboratories that have begun to embrace the concept of “visible conservation.” A permanent space in Old Falvey’s reading room has been allocated for the project, allowing students as well as the general public to observe the treatment process and even interact with the conservation team. A schedule will soon be posted, listing dates/times for formal tours and a live web-cam will add an interactive element to the project. This will help to raise awareness of contemporary conservation methods, the history of the painting, and the upcoming renovation of the Library’s reading room.

Collaboration on Campus

An exciting aspect of the project will involve the collaborative efforts of scholars, faculty, staff members, and students, interactions that will occur on a daily basis in the publically accessible conservation space. Dr. Anthony Lagalante, Dr. Amanda Norbutus, and graduate student Kristen Watts from the Chemistry Department will be working alongside the conservation team, performing pigment analysis in an effort to learn more about the materials used by Pietro and his workshop. Dr. Mark Sullivan, Dr. Timothy McCall, and senior undergraduate student Rachel Godat from Art History will be offering their expertise as well, helping the conservation team to gather more information relating to the artist, his workshop, and other aspects of the painting’s provenance. Finally, Darren Poley and the library staff will be integral in the promotion of the project and it’s connection to the upcoming renovation of the Library’s Old Wing. Future events will be announced as the treatment progress and will likely include lectures, symposia, web projects, and/or interactive workshops.

The Conservation Treatment

The treatment of the painting will be carried by painting conservator Kristin deGhetaldi over a period of two years with the help of conservation interns and graduate students (currently Maggie Bearden and Emily Wroczynski). The painting is presently covered with several layers of discolored and degraded over-paint and varnish, unoriginal materials that have aged poorly and now obscure the original colors of Pietro’s vibrant palette. Conservators are professionals who have specialized knowledge and skills in the arts, sciences, and other fields; responsibilities can include establishing appropriate environmental controls, stabilizing the structure of an object, compensating for surface disfigurement from deterioration and/or damage, and undertaking technical studies. A professional conservator conducts these activities according to the Code of Ethics of the American Institute for Conservation of Historic and Artistic Works.

In years past, those interested in becoming a conservator would typically enlist as an apprentice in a restoration studio. Today, however, most students pursue a master’s degree in art conservation after obtaining a bachelors degree in art history, studio art, the sciences, or other related fields. In order to be accepted into a graduate degree program in the United States, students must satisfy extensive course requirements (e.g. organic chemistry, art history/anthropology courses, a studio art portfolio, etc.) and complete a certain number of hours serving as a volunteer/intern in a cultural institution or private studio. This pre-program experience often takes additional time beyond completion of an undergraduate degree. Students who are interested in learning more about graduate programs should also visit the Emerging Conservation Professionals Network blog.