A composition including a core-shell polymeric particle, the core including, when dry, at least one void and the shell including, as polymerized units, from 18% to 50%, by weight based on the weight of the shell, monomer selected from the group consisting of acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, and mixtures thereof is provided. Also provided is a composition including an organic medium and a core-shell polymeric particle, the core including, when dry, at least one void and the shell having a calculated shell-organic medium interaction parameter, XPS>1.15 and a method for providing opacity to a dry composition.