Perceptual transparency

Perceptual transparency is the phenomenon of seeing one surface behind another.

In our everyday life, we often experience the view of objects through transparent surfaces. Physically transparent surfaces allow the transmission of a certain amount of light rays through them. Sometimes nearly the totality of rays is transmitted across the surface without significant changes of direction or chromaticity, as in the case of air; sometimes only light at a certain wavelength is transmitted, as for coloured glass. Perceptually, the problem of transparency is much more challenging: both the light rays coming from the transparent surface and those coming from the object behind it do reach the same retinal location, triggering a single sensorial process. The system somehow maps this information onto a perceptual representation of two different objects. Physical transparency was shown to be neither a sufficient nor a necessary condition for perceptual transparency.