Films of butanedithiol interconnected nanoparticles can exhibit a percolation-driven insulating to metal transition. To explore properties of materials with interpolating behavior, we have measured conductance of these films with systematically varying thickness. Films below a certain threshold coverage exhibit thermally assisted conductance and conductance suppression near zero bias indicative of single-electron-charging barriers. In analogy with semiconductors, we show that these films permit transistor-type gating of film conductivity.