A Dionysian Dilemma: The Conservation and Display of Oversized Pompeian Watercolors at the Kelsey Museum of Archaeology

Jamye Jamison and Wendy Partridge, Intermuseum Conservation Association
Claudia Chemello and Suzanne Davis, Kelsey Museum of Archaeology

In 2008, the Kelsey Museum of Archaeology at the University of Michigan received a grant from the Institute of Museum and Library Services (IMLS) to undertake the conservation and installation of 21 large-scale watercolors depicting the fresco cycle in the Villa of Mysteries in Pompeii. The Intermuseum Conservation Association, the nation’s oldest not-for-profit regional conservation center in Cleveland, OH, partnered with the Kelsey Museum on this project.

Installing the large watercolors.

The watercolors were commissioned by the Museum’s namesake, Francis Kelsey, in the mid-1920s. Kelsey, who was present at the Villa’s excavation in 1909, wanted to bring the excitement of this amazing discovery to students, scholars and the public in the US. He commissioned Italian artist Maria Barosso to create 5/6 scale renderings of the fresco cycle. The result is a series of watercolors that not only capture the beauty of the images, but also the condition of the frescos at the time. At Professor Kelsey’s request, Barosso was every bit as detailed in recording the cracks and losses in the plaster surface as she was in recreating the figures. Kelsey’s intent was to have the watercolors on display at the University of Michigan. Sadly, Professor Kelsey died in 1927, before they ever arrived.

For the majority of the 20th century, the watercolors remained rolled in storage in the Museum’s 1890s building. Due to their size – the largest single panel is 5 x 20 feet – the objects have only occasionally been brought out individually for educational purposes and only displayed twice as a group. The first time was in Italy at the Villa Borghese just after their completion in 1928, and more recently they were shown in a brief exhibition at the University of Michigan Art Museum in 2000. In 2005, the Kelsey Museum received a donation to build a new exhibit and storage facility. This presented the Museum with an opportunity to finally bring Francis Kelsey’s dream to life.

A major concern for both the Kelsey Museum and conservators at the ICA was the effect that prolonged exposure to light might have on the watercolors. Because the original frescos have deteriorated even further since Barosso’s renderings were completed, the watercolors are considered a key document of the condition of the frescos at the time of excavation. To gather more precise data about the pigments, the IMLS grant included provisions for non-destructive micro-fade testing of the pigments to be conducted by Dr. Paul Whitmore, conservation scientist and the director of the Art Conservation Research Center at Carnegie Mellon University.

Utilizing a focused beam of light and a spectrometer, Dr. Whitmore can document the color shift in a 300 micron area on an object. Each minute of testing approximates one year of gallery conditions, roughly 8 hours/day of exposure to light at 50 lux with UV filtered out. The test results for the Barosso watercolors showed that most of the pigments are fairly stable. However, some of the reds did test sensitive to light, darkening instead of fading as is usually the case. With such precise information, the Kelsey Museum can track the amount of light to which the watercolors are exposed over time and react accordingly to limit damage. Light levels in the gallery are set at 30 lux and activated by motion sensors.

In terms of treatment, these objects are much more complicated than just works on paper. Not only are they extraordinary in size, they are composite in structure. Barosso divided each wall of the fresco cycle into three parts; the central figural panel, and the upper and lower decorative borders. Each of these segments was painted on a separate piece of paper backed with canvas. Display of the entire set requires all panels to be mounted in such a way that they fit together as groups of three, but also within the gallery as a whole. The assembled groups are just under 10 ft tall and range from 3 ft to 20 ft long. The basic course of treatment was to remove the smaller watercolors from the Gator-board mounts used for the 2000 exhibit, unroll the larger watercolors, and prepare everything for humidification and flattening. After the watercolors were flattened, they were carefully measured for the fabrication of custom aluminum honeycomb panels.

Initially, to mount the objects to the panels, Japanese paper hinges were attached to the reverse of the watercolors with wheat starch paste. However, because of the composite structure, the wet hinging process caused too much warping over the surface of the objects. ICA conservators tried two different hinging techniques, but even after weeks under weight, the watercolors were still not flat enough to be mounted. Because the watercolor panels were backed with canvas, the project conservators started to think of them more like paintings than simply works on paper. Adhesive options were tested and BEVA film, a heat activated synthetic adhesive, was selected, both to attach the hinges to the watercolors and to mount the watercolors to the aluminum panels. This technique allowed conservators to flatten the watercolors and then attach the hinges dry using a tacking iron.

The objects are now installed in the newly built Upjohn Wing of the Kelsey Museum of Archaeology on the Ann Arbor campus of the University of Michigan. This project will be presented to the Book and Paper Group at the AIC meeting in May 2010.

For more on the murals see: