A technique is presented to produce a photograph that accurately illustrates the limits of perception for an observer's view of objects under night lighting. This may be used to show others the results of an investigation of visibility problems associated with a nighttime collision. The method, which involves the observer viewing signs of varying shades of grey at the site under appropriate conditions, and the production of a range of photographic prints from which the correct density level is selected, is described. Findings from validation testing are discussed including the expected accuracy and possible difficulties.
