Method and system for calculating the fractional exposure of photographic material

Abstract

The invention provides a method for calculating the fractional exposure of black and white photographic material, the developed material being processed in a processing system having a fixing stage and an in-line silver recovery unit associated with the fixing stage, comprising the steps of determining the mass of silver recovered by the in-line silver recovery unit during a period of operation of the method, calculating a first estimate for the fractional exposure of the photographic material in dependence on the determined mass of silver and, using said first estimate as an input to an iterative process, to calculate a subsequent estimate for the fractional exposure (θ) of the photographic material. The invention provides a simple and accurate method and system for calculating the fractional exposure of photographic material without requiring the use of a silver sensor.

Dependencies are inferred from the claim text.