Described herein is a method of producing a liquid electrophotographic ink composition comprising combining a pigment with a charge director in a carrier liquid to produce a pigment dispersion; and combining a thermoplastic resin with the pigment dispersion to produce a liquid electrophotographic ink composition; wherein the charge director comprises a metal salt of a sulfonic acid. Also described herein is a method of printing the liquid electrophotographic ink composition and a printing set comprising the liquid electrophotographic ink composition.