The present invention relates to a process for preparing dye-comprising aqueous polymer dispersions by free-radical aqueous emulsion polymerization of ethylenically unsaturated monomers in the presence of free-radical initiators, in which at least some of the monomers are employed in the form of an oil-in-water emulsion E1 whose disperse phase comprises at least one oil-soluble dye, wherein the disperse phase of E1 is formed essentially of dye-comprising monomer droplets having a diameter<500 nm.The present invention relates in addition to dye-comprising formulations which comprise the dye-comprising polymers of the invention and to pigmented formulations which comprise a polymer of the invention comprising optical brightener.