A specialized workshop term used by Rino Giannini for an introductory finishing operation carried out with pneumatic hammer, gradinetto, and chisel.
Impastatura appears in the technical video sequence of Le voci del marmo as the introduction to finishing: “impastatura con martello pneumatico, gradinetto e scalpello.” The ordinary Italian word means mixing or kneading, but here it is preserved as specialized workshop vocabulary.
Because this usage is local and technical, it should not be interpreted from the everyday meaning alone.
Etymology
From Italian impastare, ordinarily “to mix or knead”; specialized workshop usage in marble finishing.
Sculptor Notes
This is precisely the kind of term the Lexicon should preserve cautiously. The source proves the word belongs to the carving sequence; later research can deepen exactly how individual Pietrasanta carvers define the operation.
References
https://levocidelmarmo.sns.it/lista_video.php; https://www.treccani.it/vocabolario/impastatura/