Integrating Sphere Measurements On Glazing Materials With A Mixed (Specular And Diffusing) Behaviour Using Two Reference Standards

A procedure is presented to estimate the systematic error in integrating sphere measurements related to the spartial distribution of transmitted or reflected radiation in the case of samples with partly specular and partly diffusing properties. In this procedure the measurements are referrred firstly to a specular standard and then to a completely diffusing reference standard; the discrepancy between the two results gives an idea of how the bad geometry (non ideal behaviour) of the integrating sphere can perturb the measurement.