ISO 9848:1993

Photography — Source document microfilms — Determination of ISO speed and ISO average gradient

The method of determination specified is based on exposing and processing samples, measuring density from the resultant images to produce a sensitometric curve from which values are taken and used to determine ISO speed and ISO average gradient. Applies to black-and-white camera negative photographic films used for first generation microfilming of source documents at exposure times typically found with tungsten sources.