Methods for driving an electrophoretic medium including two pairs of oppositely charged particles. The first pair including a first type of positive particles and a first type of negative particles and the second pair consists of a second type of positive particles and a second type of negative particles, wherein the first pair of particles and the second pair of particles have different charge magnitudes (identifiable as zeta potentials). In particular, the driving methods produce cleaner optical stakes of the lesser-charged particles with less contamination from the other particles and more consistent electro-optical performance when the intermediate driving voltages are modified.