The film, that took five days to shoot, shows the smelting and casting process of the work known as Puertas Mallorquinas by Joan Miró.

Pere Portabella explores familiar interests and themes in this short, which documents the making of a sculpture by Juan Miró. Commissioned by the Galeria Maeght for an exhibition on the Spanish artist, Miró Forja was to be paired with Miró Tapis, each detailing a different aspect of his work.