Kilner screens

Kilner screens are collodion-coated, dye-treated glass screens, which were invented by Walter J. Kilner for the intended development of certain visual faculties by a user that would enable them to see the aura of other beings and objects, eventually to the point that they would not require the use of the screens. The blue screens contained dicyanin, which Kilner also referred to as spectauranine, a synthetic blue quinoline dye of the cyanine type derived from coal tar, while the red screens contained carmine dye.

In his book, The Human Atmosphere, Kilner described his experiments as being inspired after "reading about the actions of the N-ray upon phosphorescent sulphide of calcium."