Brilliant and angle-dependent iridescent colors were obtained from polymer films produced via colloidal crystallization of monodisperse core-shell particles by drying aqueous dispersions. By variation of the particle size, the brilliant color could be varied throughout the visible spectrum. The color effects of the smooth thin films exhibit excellent thermal and water stability. The morphology of the core-shell particles and the properties of the corresponding films were characterized by dynamic light scattering (DLS), atomic force microscopy (AFM), differential scanning calorimetry (DSC), and reflection spectrum measurements. The results indicate that the brilliance of the film is strongly dependent on size and quality of the crystalline domains.