Silver thin films deposited with ion bombardment are more durable in a humid environment, and maintain a higher value of reflectance over time, than films deposited without ion bombardment, particularly in the short wavelength range. Experimental results indicate that the surface roughness is reduced and the film becomes denser. The hardness of the film increases to nearly twice that measured by a microhardness tester. In addition, the lattice space is increased, causing the film stress to change from tension to compression. However, too high of an ion energy could trap the argon gas in the film, thus decreasing the extinction to the refractive index ratio, kin. Consequently, the resistivity increases and the reflectance decreases.