Reflectielicht

Reflectielicht is the portion of light that is redirected by a surface after interacting with it. In optics, reflectielicht is distinguished from transmitted light, which passes through the material, and from absorbed light, which is converted to other forms of energy. The amount and quality of reflectielicht depend on the optical properties of the surface, the wavelength of the light, and the geometry of illumination and viewing.

Reflection occurs in two main forms: specular reflection, where light is reflected in a well-defined direction as on a mirror, and diffuse reflection, where light is scattered in many directions due to surface roughness. The law of reflection states that for a smooth surface the angle of incidence equals the angle of reflection. For real-world materials, the intensity of reflectielicht also depends on polarization and angle of incidence, which is described by the Fresnel equations.

Reflectance or albedo is the fraction of incident light that is reflected. It ranges from 0 (perfect absorber) to 1 (perfect reflector) and varies with wavelength. Surfaces can have high reflectance in some wavelengths and low in others, giving color. Surface roughness and subsurface scattering can modify the apparent color and brightness of reflectielicht.

Applications of reflectielicht include photography and cinematography (lighting and shading), computer graphics (modeling reflectance with BRDFs), remote sensing and astronomy (albedo of planets and asteroids), and the design of optical coatings and solar panels. The measurement of reflectance is a common optical practice and is reported as spectral reflectance or luminance-based reflectance.

Related concepts include specular highlight, diffuse reflection, total internal reflection, and Bidirectional Reflectance Distribution Function (BRDF).