Whiteness is measured in terms of diffuse reflectance, which is the ratio of reflected light measured at 90deg. after passing through a suitable filter and the incident light that is generally at 45o to the surface of the samplePaper, Textiles, Food items, Pigments, Tiles and Minerals Ideal for measuring whiteness & brightness Can be used to measure both whiteness & brightness by changing filters only Standard MgCO block supplied with the instrument Simple to operate.