An optical article, comprising: a retarder film providing a first light retardation in a first zone, a second light retardation, greater than the first light retardation, in a second zone, and a third light retardation, different from the first and the second light retardation, in a third zone and comprising an effective medium stack of contiguous ultrathin layers configured to provide an effective optical medium for visible light, the ultrathin layers arranged into a plurality of optical repeat units each of which has an optical thickness of less than 190 nm, the ultrathin layers including different first and second ultrathin layers, the first ultrathin layers comprising a first polymer material exhibiting a first intrinsic birefringence, and the second ultrathin layers comprising a second polymer material; wherein the ultrathin layers of the retarder film extend continuously from each of the zones to the next; wherein the retarder, prior to exposure of said retarder film in the second zone to a first radiant beam, has a first absorption characteristic suitable to heat the effective medium stack by an amount sufficient to change the first light retardation to the second light retardation in the second zone, different from the first light retardation in the first zone, while maintaining a structural integrity of the effective medium stack, wherein the stack of contiguous ultrathin layers includes the first ultrathin layers alternating with the second ultrathin layers, and wherein each of the optical repeat units include one of the first ultrathin layers and one of the second ultrathin layers, wherein the second polymer material exhibits a second intrinsic birefringence different from the first intrinsic birefringence, wherein the first and second ultrathin layers, prior to exposure of the retarder film in the third zone to a second radiant beam different from the first radiant beam, are configured such that the effective medium stack is heated by an amount sufficient to change the first light retardation to the third light retardation in the third zone, different from the first and second light retardations, while maintaining the structural integrity of the effective medium stack. a retarder film providing a first light retardation in a first zone, a second light retardation, greater than the first light retardation, in a second zone, and a third light retardation, different from the first and the second light retardation, in a third zone and comprising an effective medium stack of contiguous ultrathin layers configured to provide an effective optical medium for visible light, the ultrathin layers arranged into a plurality of optical repeat units each of which has an optical thickness of less than 190 nm, the ultrathin layers including different first and second ultrathin layers, the first ultrathin layers comprising a first polymer material exhibiting a first intrinsic birefringence, and the second ultrathin layers comprising a second polymer material; wherein the ultrathin layers of the retarder film extend continuously from each of the zones to the next; wherein the retarder, prior to exposure of said retarder film in the second zone to a first radiant beam, has a first absorption characteristic suitable to heat the effective medium stack by an amount sufficient to change the first light retardation to the second light retardation in the second zone, different from the first light retardation in the first zone, while maintaining a structural integrity of the effective medium stack, wherein the stack of contiguous ultrathin layers includes the first ultrathin layers alternating with the second ultrathin layers, and wherein each of the optical repeat units include one of the first ultrathin layers and one of the second ultrathin layers, wherein the second polymer material exhibits a second intrinsic birefringence different from the first intrinsic birefringence, wherein the first and second ultrathin layers, prior to exposure of the retarder film in the third zone to a second radiant beam different from the first radiant beam, are configured such that the effective medium stack is heated by an amount sufficient to change the first light retardation to the third light retardation in the third zone, different from the first and second light retardations, while maintaining the structural integrity of the effective medium stack.