Abstract: A special purpose microprocessor based system, comprising weighing element, stored printing ink formulation data, and operator interface designed to aid the process of mixing defined colors and shades of printing inks from a small number of constituent basic color inks. Once the color and quantity of ink have been entered, the system prompts the operator through the mixing process by displaying constituent basic color inks and quantity to be added. The actual amount of constituent basic color ink then added is monitored by the weighing element. Repeated operation for each constituent thus ensures accurate, reproducible and error free mixing to the required formulation.