The durability of a paint vehicle can be strongly influenced by the pigments which it contains. This report describes an initial investigation of the photochemical degradation of paints formulated with a commercial poly(n-butyl methacrylate) and a variety of white pigments and extenders. Upon exposure to near-ultraviolet light this resin predominantly cross-links, eventually becoming almost completely insoluble. White pigments such as rutile TiO₂ and Green Seal zinc oxide do not alter this tendency but they do slow the cross-linking rate, probably by their ability to absorb UV light. By contrast, a non-absorbing light scatterer like barium sulfate increases the rate of cross-linking, perhaps by increasing the path length of light as it becomes diffused within the paint film. Finally, pigments such as anatase TiO₂ and Kadox 515 zinc oxide not only decrease the overall degradation by screening UV light but also increase the relative importance of chain-breaking chemistries through their photocatalytic properties. Even so, loss of volatile degradation products renders these films as insoluble as the purely cross-linked systems.