Zinc etching. First state of two. Dated and signed in the plate top left 1961 / Lino Bianchi Barriviera. One of the only two proofs of this state. Inscribed in pencil, bottom left margin, 1/2 I stato / 1961 / K 688 / Una strana radice / n: 525. On Fabriano wove paper On the verso a label by Barriviera's sister Delia Bianchi. To the platemark 405 x 294 mm, the full sheet 555 x 414
See Istituto Nazionale per la Grafica, Bianchi Barriviera, Catalogo dell'opera incisa, Rome 2011; cat. No. 729.