The Use of Granularity Measurements for Diagnosis of Fogging Effects

Abstract

The granularity of black-and-white and of colour film exposed to X-rays and y-rays increases as the photon energy increases to ~0.1 MeV, remains fairly constant over the range ~0.1 to ~0.3 MeV and then decreases at higher energies. The granularity is significantly higher for exposure to X-rays in the range ~0.04 to ~ 1.2 MeV than for exposure to light. On the basis of these facts it is proposed that measurement of granularity may provide a reliable means of discriminating between these types of exposure. Confirmation is provided by examination of several samples of fogged film.