A method of driving an electrophoretic display, the display comprising a layer of an electrophoretic medium disposed between first and second electrodes, with the first electrode forming the viewing surface of the display, the electrophoretic medium comprising a fluid and first, second, third and fourth particles dispersed in the fluid, wherein: (a) the plurality of first and the plurality of second particles bear charges of opposite polarity, the first particle being a light-scattering white particle and the second particle having one of the subtractive primary colors; and (b) the plurality of third and the plurality of fourth particles bear charges of opposite polarity, the third and fourth particles each having a subtractive primary color different from each other and from the second particles, the medium being characterized in that the electric field required to separate an aggregate formed by the third and the fourth types of particles is greater than that required to separate an aggregate formed from any other two types of particles, and the method being characterized in that the display has voltage control means capable of applying voltage differences of +V H, +V L, 0, -V L and -V H between the first and second electrodes respectively, where: + V H > + V L > 0 > − V L > − V H the method comprising, in either order: (a) displaying at the viewing surface alternately the color of the fourth particles, and the color of a mixture of the fourth and second particles by applying between the electrodes a series of first pulses alternating with a series of second pulses, the first pulses having a voltage of ± V H and a polarity which drives the fourth particles towards the first electrode, and the second pulses of having a voltage of ± V L and being of opposite polarity to, but greater duration than, the first pulses; and (b) displaying at the viewing surface alternately the color of the third particles and the color of a mixture of the third and second particles by applying between the electrodes a series of third pulses alternating with a series of fourth pulses, the third pulses having the same voltage but opposite polarity to the first pulses, and the fourth pulses having the same voltage but opposite polarity to the second pulses, the fourth pulses having greater duration than the third pulses. (a) the plurality of first and the plurality of second particles bear charges of opposite polarity, the first particle being a light-scattering white particle and the second particle having one of the subtractive primary colors; and (b) the plurality of third and the plurality of fourth particles bear charges of opposite polarity, the third and fourth particles each having a subtractive primary color different from each other and from the second particles, (a) displaying at the viewing surface alternately the color of the fourth particles, and the color of a mixture of the fourth and second particles by applying between the electrodes a series of first pulses alternating with a series of second pulses, the first pulses having a voltage of ± V H and a polarity which drives the fourth particles towards the first electrode, and the second pulses of having a voltage of ± V L and being of opposite polarity to, but greater duration than, the first pulses; and (b) displaying at the viewing surface alternately the color of the third particles and the color of a mixture of the third and second particles by applying between the electrodes a series of third pulses alternating with a series of fourth pulses, the third pulses having the same voltage but opposite polarity to the first pulses, and the fourth pulses having the same voltage but opposite polarity to the second pulses, the fourth pulses having greater duration than the third pulses.