lichtreflex

Lichtreflex, in optics, refers to the reflection of incident light from a surface, boundary, or material interface. It encompasses both specular reflections, where light is reflected in a well-defined direction producing mirror-like images, and diffuse reflections, where light is scattered in many directions and the surface appears uniformly colored from many viewpoints.

Lichtreflex follows the law of reflection in smooth interfaces, where the angle of incidence equals the angle of reflection with respect to the normal. At rough surfaces, many microfacets with different orientations cause diffuse reflection. The amount and quality of reflected light depend on the surface's reflectance, its refractive index, and wavelength; real surfaces are rarely ideal and may exhibit partial transmission as well (refraction) or absorption.

The color of a reflected light is determined by the spectral components that are not absorbed. In many contexts, the term albedo describes the fraction of incident light that is reflected. Reflectance can be quantified as a ratio and is modeled by Fresnel equations for smooth interfaces and by more complex models (e.g., BRDFs) for textured surfaces.

Applications span science and engineering: designing optical instruments, solar panels, architectural surfaces, and photography. In photography, reflectivity and catchlights influence exposure and aesthetics. In ophthalmology, the corneal light reflex is a diagnostic cue used to assess ocular alignment.

See also: reflection, light, albedo, BRDF, Fresnel equations, specular reflection, diffuse reflection.