Diego Rivera's Sugar Cane
Presently a part of the permanent collection of the Philadelphia Museum of Art (PMA), Diego Rivera's, Sugar Cane, was one of eight "portable" frescos constructed in 1931 for the Rivera retrospective held at the Museum of Modern Art. The fresco is supported by concrete applied over a metal armature, and contained within a metal frame. Three additional layers of lime and marble plaster were applied over the concrete base. Painted with raw pigments on wet lime plaster, Sugar Cane is a surperb example of Rivera’s mastery of the buon fresco technique.
In 2014, Kiernan Graves and Katey Corda were commissioned by the PMA to undertake conservation treatment of Sugar Cane. While the paint layer was found to be in a generally stable condition, detachment between support layers was occuring throughout. As a result, long, diagonal and intersecting cracks had developed in the plaster with associated displacement. The extent of the detachment was assessed to be around 85% of the total surface area and thought to be ongoing. Decohesion of the original lime plaster was also found along the base where there have been repeated cycles of repair and loss.
Conservation was intended to address the severe detachment and stabilize the painting for display, movement within the museum, possible transport beyond, as well as mitigate any ongoing deterioration. The intervention included a light surface cleaning, plaster consolidation, injection grouting, and filling and reintegration of losses.
