This invention describes a process of coprecipitating a photographic material such as a dye-forming coupler inside a base ionizable polymeric particle. Preparation of such a dispersion is performed by providing a first flow comprising a solution of a surfactant in water containing a polymer ionizable by base, providing a second flow comprising a water miscible solvent, base, water, and the photographic material, then mixing the said first and said second flow and immediately neutralizing the mixed flow to precipitate the photographic material inside the polymer particles forming a fine particle colloidal dispersion of the photographic material. The polymer dispersions of the invention are characterized by high photographic activity and high dye-stability in some cases.