It’s fitting that the musical named for her wages a similar battle as it unfolds at the Longacre Theatre. An uneven, exposition-heavy book by Carson Kreitzer and Matt Gould, and an industrial set by Riccardo Fernandez, are the show's more mechanical elements. But superb lighting design by Bradley King, an eclectic and electric score, and captivating performances are the pulsating flesh and blood that ultimately render Lempicka’s flaws like stray paint specks on canvas: keeping the work from “perfection,” maybe, but not ruining it. Ultimately, Lempicka is ravishing — and one of the best new musicals this season.