AIC's 45th Annual Meeting

This is an 18th century polychromed and gilded wooden sculpture that resides in the Main Altar of the Church San Xavier del Bac, located on the Tohono O'Odham Reservation near Tucson, Arizona. It is a living church in which the O'Odham people, formerly known as Papago Indians, still attend for various celebrations throughout the year. The church is considered to be arguably the most significant historic building in Arizona. The Immaculate is represented as a young woman standing over a half moon surrounded by a cloud and three cherubs. The life sized sculpture had been precariously standing in her niche for at least 200 years. In fact, one of the major challenges during the course of our work was to bring down the sculpture from her niche, located at a height of 19 feet from floor level and putting her back up without causing further damage. Over the years the different pieces of wood and the strips of canvas used for the joints have moved and expanded due to the changes in temperature and humidity. This is the cause of most of the cracks that can be seen on the surface and which lead to the loss of paint and preparation layers. The face, the hands of the Immaculate and the faces of the four cherubs were overpainted, possibly at the beginning of the twentieth century. The whole area of the sculpture was covered by a thick layer of dust, grime, mud daubers etc. In most of the areas the silver leaf used for the garments has sulfated dramatically and turned a rusty brown color. Over the years, other damages were caused due to neglect. The course of conservation and restoration begin in January 2016 till mid-April of the same year. Preliminary studies were done in 2015 which include chemical analysis of the paint and preparation layers, a brief research of the Immaculate history and previous documentation. Cleaning along with consolidation tests were also performed. The chemical analysis gave us the composition of the different stratigraphic components. We were able to identify the original paint layer as well as the over paints. In the case of the carnations, the chemical analysis and the study of the surface through ultraviolet light was crucial for the identification of the repaintings which allowed for their appropriate removal. Structural consolidation includes the filling of large cracks with balsa wood and wood paste. Paint layer consolidation done by injection using natural glue, following the composition of the original material. The removal of the over paintings, mud daubers and non-original substances using the appropriate products and tools for each task. Volume filling done using traditional stucco. Inpainting was applied with water colors and conservation varnish colors (Maimeri®). The technique used to distinguish the original paint layer from the intervention is called tratteggio (three lines crossing, of three different colors or shades). For the last phase, a natural varnish was applied as a protective layer.