A thermoplastic composition comprising a matrix of a polycarbonate polymer in which are embedded polysiloxane domains with an average domain size between 20 and 45 nanometers. Said compositions can be obtained by combining a first polycarbonate/poly(diorganosiloxane) copolymer; with a second polycarbonate/poly(diorganosiloxane) copolymer. A range of translucencies are obtainable by varying the relative amounts of the two copolymers without substantial loss in impact properties.