The magician does so by suppressing the optical information for what really happened or by preventing the observer from picking it up and, more rarely, by artifically producing information for the impossible happening. The literature of magic is full of practical wisdom about how things are seen, but it makes little reference to physics or optics. The light must come from the edges of the proscenium arch and, according to Burlingame’s Magician’s Handbook “with reflectors throwing the light in the face of the audience.” The walls and floor of the stage are covered with black velvet, which has the lowest reflectance of any surface known. The original experiment was Metzger’s, the observer’s eye being confronted with a homogeneous “Ganzfeld” as contrasted with a surface having “microstructure.” A person dressed in white can be seen, and so can any object with a surface of higher reflectance.