The present invention relates to a method of producing silver films having large nanoparticles caused by cracking during anaerobic annealing to provide surfaces that exhibit increased metal enhanced fluorescence. Preferably the annealing process is conducted on a silver film having a thickness from about 14 to 17 nm for about an hour at a temperature of approximately 190° C. to about 210° C. resulting in the conversion of the just-continuous films into large particulate films, not readily assessable by other chemical deposition techniques.