Reflectance paper is a surface that contains a lattice of mirrored dimples. The paper is printed with color and the angle-dependent reflectance function for each pixel of an image captured with a light field camera such as Lytro. The image then displays differently depending on the angle of incident light in the viewing environment. The technique can be used for example to display the image of a sculpture with its direction-dependent shadow depending on the incidence angle of the light.
History
As of 2012, researchers at the University of California, Santa Cruz, Hewlett-Packard Laboratories and 3M had together created the first such paper, using a hexagonal lattice of millimeter-sized dimples. Dimple depth was 50 µm, representing 70% of a hemisphere. Mirroring used silver or sputtered aluminum. A 32x32 matrix of light-field information was printed on a transparent mask over the dimples.