The optical properties of films cast from latexes comprising TiO2 particles encapsulated in poly(styrene-co-n-butyl acrylate) prepared by miniemulsification and having high loading (11-70% pigment volume concentration (PVC)) were investigated. Contrast ratio (CR) measurements for all batches showed that a 3 mil film (obtained at 43% PVC) was the minimum thickness at which 98% CR could be achieved. Also, the greatest hiding power (HP) (535 ft(2)/gal) was obtained at 43% PVC. In addition, gloss measurements showed that as the TiO2 loading increased, the gloss decreased, indicating that the increasing amount of TiO2 contributed to a reduction in the surface smoothness. The effects of surfactant concentration (sodium lauryl sulfate) on the encapsulated particle size and the optical properties of the encapsulated films for the 11% PVC system are described. The effect of varying the sonifter operating conditions on the TiO2 particle size, encapsulated particle size, and the optical properties of the encapsulated films for the 43% PVC system was also investigated. A comparative study of the optical properties of films cast from encapsulated latex particles with films cast from physical blends of polymer particles and pigment at the same TiO2 loading and film thickness was made. The optical properties (i.e., CR and gloss) showed a clear advantage of the miniemulsification process over the blends. (c) 2006 Wiley Periodicals, Inc.