A variable transmittance optical filter comprising: a first layer comprising a first substantially transparent substrate with a substantially co-planar (SC) electrode system disposed thereon, the SC electrode system made of transparent electrically conductive material and comprising at least one pair of electrically separate electrodes arranged in a substantially co-planar manner on the first substantially transparent substrate, each pair of electrically separate electrodes comprising a first electrode and a second electrode, a second layer proximate to the first layer and comprising a transition material that darkens in response to a non-electrical stimulus and lightens in response to application of an electric voltage; and an electrical connection system for electrically connecting the SC electrode system to a source of electric voltage.