On the Nature of Perceptual Translucency

Translucency is an appearance attribute used to characterize materials with some degree of subsurface light transport. Although translucency as a radiative transfer inside the medium is relatively well understood, translucency as a perceptual attribute leaves much room for interpretation. Our understanding of the translucency perception mechanisms of the human visual system remains limited. No agreement exists on how to quantify perceived translucency, how to compare translucency of multiple objects and materials, how translucency relates to transparency and opacity, and what are the perceptual dimensions of it. We highlight the challenges in perception research arisen by these ambiguities and argue for the need for standardization.