Fluorescence blinking of silver nanoparticle films is observed when illuminated with red light (635 nm). The observed power-law off-time distribution is attributed to random surface diffusion and subsequent agglomeration of atomic Ag leading to the formation of photo-active Ag nanoclusters. These nanoclusters can in turn diffuse randomly to form non-emitting Ag clusters after aggregation with another Ag species. This is revealed in the power-law on-time distribution. Silver oxides found on the surfaces of Ag nanostructures are important for photoblinking to take place since nanostructures with a protective layer of polymeric citrate or cetyltrimethylammonium bromide (CTAB) against atmospheric O(2) do not display obvious emission intermittency.