Cain Slaying Abel entered The Courtauld Gallery in 1978 and is now on view again, fully conserved. Its condition – with warped panels, splitting joins, scratches and an uneven surface with areas of paint loss and yellowed and opaque varnish – had been a long-standing concern. At some point during the nineteenth century, a lattice of wood, known as a cradle, was applied to the reverse of the panel. This was intended to prevent the planks from moving but had caused stress to the panel support and had also attracted woodworm.
During the eleven-month procedure, the cradle was removed, a delicate operation; the small woodworm holes were filled with cellulose fibers; and parts of earlier restorations that had compromised the painting were carefully removed, as was the yellowed varnish. Conservators also had to find precise matches for the pigments and glazes where restoration was needed in order to stabilize the painting for the next one hundred years.
Conservators made many exciting discoveries throughout the process. Dendrochronology has dated the painting to between 1600 and 1612, and ultraviolet photographs and X-rays showed that Rubens amended the composition of Cain’s club-wielding arm and the positioning of one of his eyes. In addition, infrared imaging revealed line drawings beneath the tree in the background – which is unusual for Rubens and could be the work of a landscape specialist, indicating that Rubens may already have established a workshop at this early stage in his career.