This paper describes motor vehicle lamp assemblies employing a mask that controls the photometric output, or cosmetic appearance of the lamp. The mask is comprised of materials such as liquid crystal or electro-optic and electrochromic films or coatings. Such materials exhibit optical anisotropy based on the application of an electric current. A drive circuit is coupled to the mask and controlled by the motorist or a programmable microprocessor. The optical conditions of various sections of the mask are altered by the applied voltage from this controller. The photometry and colorimetric values at any point in the beam pattern can be altered. The mask also can be constructed to produce various cosmetic appearances, including lamp concealment.