ISO 9848:2003 specifies a method for determining the ISO speed and ISO average gradient of black-and-white camera negative photographic films used for first generation microfilming of source documents at exposure times typically found with tungsten sources. These source documents include any handwritten or printed alphanumeric and line documents such as books, periodicals, business correspondence, and engineering drawings. The value-rating system described in this ISO 9848:2003 is only useful to the consumer if his exposure illumination is from an incandescent tungsten source. It is not intended to include pictorial or continuous tone reproduction, computer output microfilm (COM), reversal processed or direct positive films or other films exposed by non-tungsten sources such as laser or cathode ray tube.
The ISO speed and ISO average gradient values obtained by applying this ISO 9848:2003 are intended for practical use in comparing film/process combinations and for computing exposures.