In the last BPG session of this year’s AIC meeting, “global conservation” took on a whole new meaning. Maria Gabriela Mayoni, a conservator of cultural heritage from the Colegio Nacional de Buenos Aires, Argentina, delivered a lavishly illustrated lecture concerning the conservation of a papier-mache globe and its support. This globe, manufactured in Germany in 1850 and bearing site labels in French, belongs to the Department of Geography of the Colegio Nacional and illustrates the European influence on Argentina during the nineteenth century–a period of nation-building and economic development. At some point in the past, the rare globe was seriously damaged in an accident: a large section was crushed, a portion of the papier-mache sphere was lost, and the support rings were deformed. The varnish coating the globe had also darkened and discolored, making the labels and land masses hard to read. The area representing Argentina had been overpainted, perhaps to keep up with changing geopolitical boundaries.
Mayoni described the complex structure of the globe, which included a papier-mache sphere with outer layers of cast composite, paper labels, paint, and varnish. This globe was mounted on a wooden axis, fitted with metallic rings, and placed on a stand made of iron and wood. All of these elements were addressed during the comprehensive conservation treatment of the globe.
Prior to beginning treatment, Mayoni and her colleagues analyzed the materials present on the globe with FTIR, and the results were consistent with an oil and natural resin varnish. This was cleaned with a mixture of water and ethanol, which was applied carefully to avoid disturbing the water-sensitive inks on the printed labels. After the varnish had been reduced, the conservators split the globe into its two original halves. Inside, they discovered labels containing information about the globe’s manufacture, including a date decades earlier than they had anticipated. The crushed portions of the globe were humidified and reshaped, and the losses were filled with a vinyl acetate adhesive and long-fibered paper. After the sphere had been mended from the inside, the two halves were reassembled, and the join was reinforced with cotton fibers. A combination of animal glue and calcium carbonate was used to fill the losses in the topographical relief. The deformed metal rings were reshaped, polished, and given a protective coating. The wooden elements of the stand were also reshaped as necessary to return the globe to usefulness.
Mayoni noted that the varnish selected during treatment will have to be replaced in a second conservation campaign. The reassembled sphere was varnished with a soft synthetic resin soluble in white spirits. Harder, solvent-soluble resins were rejected because the solvents used to reverse them would have affected the inks on the labels. However, the soft resin has become yellow and grimy since it was applied. After further testing, it will be replaced with something more durable and colorfast.
The globe is once more in use in the Geography Department of the Colegio Nacional de Buenos Aires, where the students and faculty learn the importance of preserving their cultural heritage as well as their place on the map.