Regarding Callas's acting ability, vocal coach and music critic Ira Siff remarked, "When I saw the final two "Tosca"s she did in the old I felt like I was watching the actual story on which the opera had later been based." Callas was not, however, a realistic or verismo style actress: her physical acting was merely "subsidiary to the heavy "Kunst" of developing the psychology of the roles under the supervision of the music, of "singing" the acting... Suffering, delight, humility, hubris, despair, rhapsody—all this was musically appointed, through her use of the voice flying the text upon the notes." Seconding this opinion, verismo specialist soprano Augusta Oltrabella said, "Despite what everyone says, [Callas was an actress in the expression of the music, and not vice versa."