reflectivitycan

Reflectivitycan is a hypothetical reference object used in educational and theoretical discussions of optical reflectivity. The term denotes a can-shaped target whose exterior surface can be prepared with different finishes to illustrate how surface properties influence reflected light. It is not an established commercial device but a common example in textbooks and lectures to discuss luminance, reflectance, and calibration.

In practice, typical designs describe a right circular cylinder with flat ends for simplicity in ray-tracing analyses. Exterior coatings include a high-reflectivity specular finish (such as protected aluminum or silver) or a diffuse white finish near Lambertian reflectance. Interior surfaces may be uncoated or treated to serve as a light-absorbing reference.

Optical properties and use: Reflectivity is quantified as the ratio of reflected to incident light at a given wavelength. For the specular variant, reflectivity can exceed 95% in the visible range; for diffuse variants, apparent brightness depends on viewing angle. In teaching and research, reflectivitycans are used with spectrometers or goniophotometers to calibrate instruments and demonstrate angle-dependent reflectance.

History and status: The concept has appeared in physics education since the late 20th century, but there is no standardized specification or commercial product under this name.

See also: reflectance, albedo, calibration target.