A reflective wire grid polarizer (WGP) can include an array of wires 12 on a face of a substrate 11, with channels 15 between adjacent wires 12. The wires 12 can have certain characteristics for WGP performance, such as index of refraction, alternating high/low index continuous thin films, thickness of layer(s), duty cycle, reflective rib shape, a curved side of transparent ribs 21 or 32, aspect ratio, or combinations thereof.