Ralph Steadman The Posterior and Middle Mediastinum PrintRalph Steadman's The Posterior and Middle Mediastinum Print. The print is authentically stamped and certified by the Ralph Steadman team. It's a museum quality un signed print that's custom printed with lightfast pigment inks on beautiful 315gsm acid free cotton rag paper with a natural white base. All prints are produced in Rochester, England by longtime collaborator Rikard sterlund then stamped with an official Ralph Steadman authentication stamp,