An electrostatic printer comprising: a photoconductor member; an imaging unit configured to generate a latent electrostatic image on the photoconductor member; an interface configured to receive a developer unit comprising a colored toner, the developer unit configured to develop a colored toner image on the photoconductor member using an associated base developer voltage; and a controller, wherein the electrostatic printer is characterised in that the controller is configured to: obtain image data comprising first color separation data representing the colored toner and second color separation data representing a variant color of the colored toner having a different color density; control the imaging unit to generate on the photoconductor member a latent electrostatic image corresponding to the first color separation; control the developer unit to develop, using a base developer voltage, a toner image on the photoconductor member; control the imaging unit to generate, on the photoconductor member, a latent electrostatic image corresponding to the second color separation; and control the developer unit to develop, using a variant developer voltage, a toner image on the photoconductor member, wherein the variant developer voltage is different to the base developer voltage. a photoconductor member; an imaging unit configured to generate a latent electrostatic image on the photoconductor member; an interface configured to receive a developer unit comprising a colored toner, the developer unit configured to develop a colored toner image on the photoconductor member using an associated base developer voltage; and a controller, wherein the electrostatic printer is characterised in that the controller is configured to: obtain image data comprising first color separation data representing the colored toner and second color separation data representing a variant color of the colored toner having a different color density; control the imaging unit to generate on the photoconductor member a latent electrostatic image corresponding to the first color separation; control the developer unit to develop, using a base developer voltage, a toner image on the photoconductor member; control the imaging unit to generate, on the photoconductor member, a latent electrostatic image corresponding to the second color separation; and control the developer unit to develop, using a variant developer voltage, a toner image on the photoconductor member, wherein the variant developer voltage is different to the base developer voltage. obtain image data comprising first color separation data representing the colored toner and second color separation data representing a variant color of the colored toner having a different color density; control the imaging unit to generate on the photoconductor member a latent electrostatic image corresponding to the first color separation; control the developer unit to develop, using a base developer voltage, a toner image on the photoconductor member; control the imaging unit to generate, on the photoconductor member, a latent electrostatic image corresponding to the second color separation; and control the developer unit to develop, using a variant developer voltage, a toner image on the photoconductor member, wherein the variant developer voltage is different to the base developer voltage.