Embodiments of a biometric system with an optically adaptive interface are described. In some embodiments, an optically adaptive interface changes optical characteristics in response to the placement of a finger on the optically adaptive interface. In some embodiments, the optically adaptive interface can include an active layer and a surface layer. The active layer and the surface layer can have different optical properties. For example, one layer may be opaque and the other transparent, the two layers may have complementary colors, the two layers may have orthogonal polarization reflectors, one layer may be reflective and the other absorptive, etc. Moreover, the active layer can be a fluid with either high or low viscosity. For example, the viscosity can be such that the active layer fluid is either completely displaced or not displaced in locations corresponding to finger valleys.
