Spectral radiance factors: Measurement by a gonioradiometric method

Abstract

An experimental procedure is given for measuring the distribution of light intensity reflected by materials commonly used in interiors. Measurements are carried out in the spectral domain, using a spectrophotometer as detector. They are restricted to the plane of incidence. Preliminary results for grazing incidence show that these materials do not generally behave as uniform diffusers. This conclusion could be important in lighting simulations where the Lambert law is always used extensively. The specular component tends to desaturate the colour of the sample.