The preparation of concentrated seed latices for use in bimodal and trimodal formulations is presented in the current work. Various recipes of surfactant and initiator were tested in order to allow us to control the number of particles produced during the nucleation stage. Following this, a semi-batch feed recipe that combined the use of oil-soluble initiators and pre-emulsified monomer was used to produce well-defined latices having well defined particle size distributions. It was found that the primary concern in maintaining latex stability and favorable viscosity was the reduction of undesirable secondary nucleation.