Information on the two artists Nicolò and Sebastian Nicolin Roccatagliata is scarce. Nicolò Roccatagliata was born in Genoa and was apprenticed to the jeweler Agostino Groppo from 1594-1595. He lived in Venice, where he spent time with Tintoretto and sculpted works for the basilica of San Giorgio Maggiore. His son, Sebastian Nicolin, remains obscure. In 1636 he worked in various churches in Venice including St. Mark’s basilica and the church of Santi Giovanni e Paolo. The present relief may not have been conceived as an altar paliotto as the observation point favours a view from bottom up. Considered by critics to be a masterpiece by the Roccatagliatas, the paliotto was made in 1633, as shown by the inscription. The subject is difficult to decipher and very striking in its wavering from didactic adherence to the holy writings to expressive accentuation of the narrative and poetic vision. The picture is tripartite: in the center e the dead Christ is supported by winged putti with the Eternal Father above; on the right the Marys and St. John with the Gospel supported by an eagle and, on the left, the preparation of the sepulcherwith Joseph of Aramathea on the right with various onlookers.
The paliotto was made with the technique of lost wax casting. After it had been dismantled, observation from the reverse clearly indicate that it had been made in several parts using a fairly complex and unusual method. All the protruding figurative elements were cast separately and placed in holes made for them in the base, which in turn is in three parts. The joins were covered with a filler of resin and wax, which in many areas was cracked, partly detached and, near the edges, with many losses due to the advanced stage of deterioration in these areas. An x-ray study was made of the entire work to find out how the various parts were fastened to one another. This showed the almost complete absence of soldering and considerable variation in the quality of the casting. The signs of a cutting instrument, visible along the edges of the more protruding parts and their seats in the base, suggest that these elements were applied with a mechanical system of embedding by means of beating. Before the restoration the entire surface was covered with an opaque blackish layer of dust and splashes of wax, which made it difficult to read the details of the piece. The worst deterioration was at the edges, where thick concretions of copper corrosion products were evident, made up mainly of chlorides and carbonates. The diagnostic work sought to the most correct and selective approach to the work. A first layer of drying oils in direct contact with the metal was identified, which was probably the surface finish intended by the artist over a chemically induced glaze. A mixed layer of waxes was found over the oils, added in subsequent maintenance works. Solubility tests with various solvent mixes were carried out to identify the most suitable cleaning method that would respect the original patina, removing only the layers above. The incrustations of corrosion were mechanically removed with the help of scalpels, micro-motors and vibro-engravers. Various washing cycles were then carried out with deionised water and treatments made to inhibit active corrosion; finally, the surface was protected with microcrystalline waxes especially formulated for the protection of metal objects.