Reflectance Standards

Definition

A reflectance standard is a physical reference sample that includes ratio values between the total amount of radiation, as of light, reflected by a surface, and the total amount of radiation incident on the surface across the visible spectrum. Reflectance standards are used for the calibration and verification of spectrometers. There are two kinds of reflectance standards: diffuse and specular. In practice, white and black reflectance standards are utilized for calibration. They require a similar specular or diffuse surface property to the device under test (DUT).

Applications

Diffuse and specular reflectance standards are used to calibrate colorimeters, reflectometers, spectroradiometers, bidirectional reflectance distribution function (BRDF) scatterometers [1], ultraviolet–visible (UV–VIS) spectrophotometers, and Fourier transform infrared (FTIR) spectrometers.

Diffuse white reflectance standard samples can be obtained with diffuse reflectance of 98 % or more. Some...