Method of producing pigment dispersion

A method of producing a pigment dispersion having a characteristic color by additive color mixing, the method comprising the steps of:

• preparing a solution in which two or more color pigments with a controlled ratio of the pigments and a dispersant are dissolved in a solvent containing an aprotic organic solvent in the presence of an alkali;
• preparing a medium that decreases a solubility of the two or more color pigments by being added to the solution;
• preparing a mixing device comprising a plurality of tubes, which each have a respective opening size ranging from not less than 10 μm to not more than 3,000 μm, to eject a liquid into open air, wherein the tubes and a vessel to receive the pigment dispersion are arranged such that liquids ejected from the tubes contact with each other to be merged as one flow to fall gravitationally and then be received in the vessel disposed downward of the merged point;
• feeding the solution and the medium to the tubes to eject the solution and the medium into the open air without scattering the solution, wherein the solution and the medium are ejected from the respective tubes and are caused to contact and mix with each other in the open air;
• and
• depositing the two or more color pigments by contacting the solution and the medium in the open air.