Crystalline colloidal arrays have been used for a variety of purposes. A crystalline colloidal array (CCA) is an ordered array, typically produced from monodispersed colloidal particles, which may be composed of inorganic or organic materials. Such CCAs are often provided in a hexagonal close-packed (HCP) or random hexagonal close-packed (RHCP) structure and may exhibit a layered structure with a preferred diffraction axis that is perpendicular to the layers in the structure. The diffraction wavelength varies with the angle of incidence to these layers. When fixed in a binder as a colorant, such CCAs can diffract radiation in the visible spectrum. These colorant CCAs may exhibit a goniochromatic effect when applied to a substrate.