Noble metal thin films have been used for surface enhanced Raman scattering nearly since its inception, but only recently has single molecule detection been demonstrated on these types of films. Image analysis of the surface optical response on a native thin silver film during excitation revealed a dynamic system that blinks and photobleaches with time. A mechanism involving silver clusters as an emitting species is presented and discussed in the context of the integrated frequency-shifted intensity as a function of time. (C) 2004 Elsevier B.V. All rights reserved.