Abstract: A Psychophysical Perception Enhancement, for use in juxtaposition to a perceptible output spectrum, and the enhancement includes: (a) designating a target enhancement region in the spectrum and the region is defined as having at least one boundary; (b) proximate to one of the boundaries, defining a perceptible transition region; and (c) in the transition region, applying a filter having a spectral shape substantially inverse to normal perception for the transition region. The enhancement is preferably applicable to a visual or audio systems and can be embodied as a digital, analog, mechanical, passive, optical element.