A control system for regulating the composition of an emulsion ink made from an oil-based ink and a water-based fountain solution using a mixing and dispersing apparatus includes a liquid level sensor, means responsive to the liquid level sensor for maintaining a proper liquid level in the mixing and dispersing apparatus, and means for producing an emulsion ink with a water content value which is within a predetermined range from a desired water content value. The producing means includes a feedforward controller and a feedback controller for regulating water-based fountain solution input rate to the mixing and dispersing apparatus.