Imaging element and method for making a lithographic printing plate according to silver salt diffusion transfer processing

An imaging element for making a lithographic printing plate according to silver salt diffusion transfer processing, said imaging element comprising on a support a silver halide emulsion layer and a receiving layer, said receiving layer comprising (i) physical development nuclei, (ii) an inorganic colloidal substance and (iii) a hydrophilic polymer which is a homo- or copolymer of acrylamide or methacrylamide, wherein said inorganic colloidal substance is a synthetic smectite clay or a synthetic laponite clay and wherein said physical development nuclei have an average diameter less than 6 nm and the number of nuclei having a diameter larger than 4.5 nm is less than 15% of the total number of nuclei.