This disclosure provides systems, methods and apparatus for providing illumination by using a light guide to distribute light. In one aspect, the light guide includes a light turning film over an optically transmissive supporting layer. The light turning film may be formed of a material deposited in the liquid state. The light turning film may be formed of a photodefinable material, which may be glass, such a spin-on glass, or may be a polymer. In some other implementations, the glass is not photodefinable. The light turning film may have indentations that define light turning features and a protective layer may be formed over those indentations. The protective layer may also be formed of a glass material, such as spin-on glass. The light turning features in the light guide film may be configured to redirect light out of the light guide, for example, to illuminate a display.