The Nineteenth Hurter And Driffield Memorial Lecture Developments and Trends in Practical Exposure Determination

Abstract

The encouraging progress which has been made in international film speed standardization during recent years is briefly reviewed. Some practical reciprocity failure considerations are then discussed and accompanied by a modified table of corrections for long camera exposures. A few relevant aspects of tone reproduction are emphasized, including the desirability of minimizing lens flare and internal camera reflections particularly for colour work. Recent developments and trends in standardized exposure tables, photo-electric reflected-light exposure meters and selective exposure photometers are then discussed, and various methods of applying photo-electric incident-light meters are reviewed. Finally a new “back-leak” incident-light receptor arrangement is described which gives optimum results with a single meter reading under all practical lighting conditions including side and up to full back lighting. Designed primarily for use with colour and monochrome reversal materials and for motion picture work generally, this arrangement is also showing signs of giving good results with general purpose negative materials.