Optimal daylighting of a room using prism lighting. The prism tile canopies mounted outside over the windows send light skimming across the ceiling, so that workers deeper in the room also have natural light coming over their left shoulders. Multiple prescriptions of prism tiles are used, so some light is also sent horizontally and slightly downwards.[1]
The reflection-based daylight redirecting film, stuck to the inside of top part of the windows, is reflecting light sharply up onto the ceiling. This is a suboptimal use of prism lighting. While the ceiling does diffuse the reflected light, it still mostly lights the area nearest the window, where it is superfluous. However, glare is reduced without reducing the amount of daylight in a room.
The same film in a similar room, but at another sun angle. The light is reflected at a shallower angle, lighting the room more evenly.
Daylight redirecting film (DRF) is a thin, flexible plastic film which can be applied to a window to refract or reflect incoming light upwards so that the deeper parts of the room are lit more evenly. It can be used as a substitute for opaque blinds.[2] It is a form of prism lighting.