An image forming medium includes a substrate; an imaging layer including an imaging material coated on said substrate, wherein the imaging material exhibits a reversible transition between a colorless state and a colored state; and a protective layer over the imaging layer, the protection layer including dipolar molecules that can be reversibly switch between a UV light transmission state and a UV light absorption state, wherein the dipolar molecules in their random orientation absorb in substantially the same spectral region as the imaging material in its un-imaged state, and wherein the imaging layer is imageable by ultraviolet light when the dipolar molecules are in the UV light transmission state, but the imaging layer is substantially not imageable by ultraviolet light when the dipolar molecules are in the UV light absorption state.