Backplate. A plain metal plate that is soldered to a galvano, electroform, shell, uniface casting, or a hollow struck piece to close off its back side (usually forming a hollow space inside). A backplate could be considered the blank reverse of this uniface piece. The area inside, whether cast hollow or hollow from its being closed off, reduces the weight in contrast to having the piece cast solid. Lettering may appear on the backplate, as maker's marks, foundry marks or hallmarks; or a hanger may be attached to the backplate. A seam would be visible on the edge between the backplate and the obverse cast or shell; the edges are usually smoothed and polished. Though they are seldom seen, backplates are customarily colored or patinated the same as their companion obverses. The presence of the backplate should be noted in cataloging such a piece.