Abstract: A process of producing a non-conductive ink formed from colorant particles and a non-conductive carrier liquid where the colorant particles are inherently of a low electrical resistivity. The process includes the steps of applying to the surface of the colorant particles a material with a high electrical resistivity to give the particle a higher surface resistivity and blending the treated colorant particle with the non-conductive carrier to form the non-conductive ink. The insulative material may be selected from polymers, waxes, organic pigments and dye stuffs and the colorant may be carbon black, magnetic iron oxide or metallic powder.