An apparatus for developing a latent image recorded on an imaging surface with a custom color toner, including a developer housing for developing a portion of the latent image with the toner of custom color. The developer housing includes a donor member for transporting toner of the custom color to a development zone to develop the latent image. A replaceable reservoir unit is provided for mixing and supplying the custom color toner to the donor member. An array of toner dispensers is provided for supplying various primary color toners, as required, to achieve the custom color, and additional reservoirs having various colored toners therein to allow for faster convergence to a given point in the color space.