A liquid developer system contains electrically charged toner particles that are applied to a surface having a latent electrostatic image thereon for developing the image. The liquid developer system includes an insulating non-polar carrier liquid, toner particles dispersed in the carrier liquid, and at least one charge director compound that is only partially soluble in the carrier liquid. The charge director compound is supplied in solid form to the carrier liquid in excess of the amount that achieves saturation concentration. As a result, the compound is in equilibrium contact with the carrier liquid and maintains a predetermined concentration of dissolved charge director in the liquid developer system.