Polymeric particles comprising a polymeric matrix and colourant distributed throughout the matrix, wherein the polymeric matrix that has been formed from a blend of monomers comprising a first monomer which is an ethylenically unsaturated ionic monomer and a second monomer which is an ethylenically unsaturated hydrophobic monomer which is capable of forming a homopolymer of glass transition temperature in excess of 50° C., and in which the first monomer is a salt of a volatile counterion component, characterized in that the polymeric matrix is impermeable to the colourant The particles obtainable by the process of the invention can be used in a variety of industrial processes, for instance in the manufacture of inks, paper and cosmetics.