During the drying of the pigment press cake, primary particles join together to form aggregates and agglomerates. Despite milling of the dry pigment by producers, these aggregates and agglomerates are not completely broken down.

It remains the job of the pigment user to further breakdown the aggregates is a dispersion process to achieve the optimum properties of the pigment. This dispersion process requires intimate wetting of the pigment by the polymer to achieve optimum dispersion. This is often difficult with polymers which have poor wetting characteristics and high viscosities.

The flushing process by-passes this pigments with optimum particle size is dispersion step. A press cake containing mixed with the carrier, such as a wax. Under the right processing conditions, and in the presence of suitable additives, the pigment transfers from the aqueous phase (press cake) to the organic phase (wax) while retaining the original size. The result is a dispersion of the pigment in the wax that retains the original particle size of the pigment at high concentrations